At a recent debate between the Democratic presidential candidates, Sen. Hillary Rodham Clinton was asked to describe the most important policy differences between her and Sen. Barack Obama, her rival for the nomination. Health care topped Clinton's list. "I believe absolutely, passionately, that we must have universal health care," she responded. "It is a moral responsibility and a right for our country."
Policy distinctions between the top Democratic candidates are subtle, centering on health insurance mandates, political reforms, and Iraq.
Clinton's answer accentuated her plan's mandatory coverage for everyone -- a standard that, she argues, his proposal fails to meet. The senator from New York has emphasized that difference at every opportunity -- on the stump, in TV ads, and in almost every debate between the candidates.
But when the senator from Illinois had a chance to respond, he tried to scuttle the notion that they were at such dramatically different places. "About 95 percent of our plans are similar," he said. Sure, Clinton would mandate coverage for everyone while he would focus on making insurance affordable and require parents to cover their children (a partial mandate) -- but, in the end, Obama insisted, both of them have pretty much the same goals.
In fact, even as the two Democratic presidential candidates try to highlight their differences on health care and other issues, an examination of their votes since Obama arrived in the Senate in 2005 shows that they have strikingly similar records. On the 888 Senate questions on which they have both voted (through February 15), they have disagreed just 52 times.
Indeed, it is their difference in style -- Obama's inspirational oratory versus Clinton's can-do pragmatism -- that is most striking, while their positions on policy are so comparable that three of five Democrats want them to run on the same ticket, according to a Bloomberg/Los Angeles Times poll taken last month.
When strong Democratic constituencies, from organized labor to environmentalists, are asked to evaluate the candidates' positions on issues of greatest importance to the groups, they often respond with praise for both Clinton and Obama.
"The consensus among most unions is that these are two really good candidates," said Denise Mitchell, a spokeswoman at the AFL-CIO. "The truth is, we believe their positions are very similar."
"The differences are more touchy-feely than substantive," added labor strategist Victor Kamber. He noted that although more unions support Clinton than Obama, the disparity reflects Clinton's deep ties to labor over the years. "The big difference is that she can walk into a meeting and she knows the [union] presidents and the lobbyists and the key people by name, and he doesn't," Kamber added.
On the environmental front, the verdict is the same: The differences between the candidates are on the margin. They have nearly identical positions on global warming, nuclear energy, and related issues. Their most notable difference came to light in 2005, when Obama voted for the Energy Policy Act, which passed overwhelmingly. Clinton and the environmental lobby opposed it, in part because of its goodies for the oil and nuclear industries, including billions of dollars in tax breaks.
Obama said he backed the bill because it included provisions to double the use of ethanol and provide additional funding to develop coal-fired electric plants that produce less pollution than current ones. That vote was a no-brainer for the 46-year-old senator, whose home state counts corn and coal as major industries. Despite Obama's position on that legislation, Sierra Club Executive Director Carl Pope said that "on environmental issues, we do not see a big substantive difference" between the two Democrats.
Similarly, not much separates the candidates on trade. Both of them have heard and responded to the searing critique of free-trade deals leveled by party activists who see the agreements as flawed because their weak labor and environmental standards have led to job losses. The critics point to the growing trade deficit with China and the ever-growing practice of outsourcing that has led to the lowest level of employment in the manufacturing sector in more than 50 years.
Recognizing the potency of these arguments to Democratic primary voters, both Clinton and Obama opposed the Central American Free Trade Agreement and said they would vote against the trade agreements with Peru and South Korea in their current forms. They have also criticized the North American Free Trade Agreement, a deal that continues to infuriate many activists who argue that President Clinton hyped the deal's benefits when he vigorously pressed for its passage in 1993.
"They are pretty similar" on trade policy, said the AFL-CIO's Mitchell. "There is more of an acknowledgment than there was 10 years ago that these trade agreements aren't working so well -- that they aren't the solution, that we need some different global rules, certainly not to try to shut down our borders, but different global rules. Both of them agree with that."
Also, on foreign-policy issues in general, "ultimately their goals are the same," said Moira Whelan, director of strategy and outreach at the National Security Network and an Obama supporter. "Their understanding of what the macro issues are is similar; their approaches to what comes first and how to address them is where you would see the differences."
Hyping Their Differences
Perhaps because of their similar positions on so many issues, Obama and Clinton go to great lengths to differentiate themselves and appeal to primary voters by stressing whatever distinctions they can. Obama tees up his early opposition to military action in Iraq as evidence that he exercised better judgment than Clinton on the most important foreign-policy issue since the terrorist attacks on September 11, 2001.
In a 2002 speech in Chicago, when he was beginning his campaign for the Senate, Obama blasted what he called "a dumb war" that was "based not on reason but on passion, not on principle but on politics."
Graphic: Where They Differed Sens. Hillary Rodham Clinton and Barack Obama have differed on 52 of the 888 measures they have both voted on in the Senate. This graphic shows the candidates' differences and how each voted.
Obama noted at a debate on January 31 that Clinton says her experience has prepared her to lead "on day one," but that his opposition to the war shows that "it is important to be right on day one." His judgment on that issue, Obama added, is relevant to how he would make decisions in a dangerous world.
But just as Obama minimized his differences with Clinton on health care policy, Clinton is quick to say that their positions on Iraq are far more similar than her rival suggests. "He gave a very impassioned speech against [the war] and consistently said that he was against the war, he would vote against the funding for the war," she said on NBC's Meet the Press on January 13. "By 2004, he was saying that he didn't really disagree with the way George Bush was conducting the war. And by 2005, '06, and '07, he was voting for $300 billion in funding for the war.... When he became a senator, he didn't go to the floor of the Senate to condemn the war in Iraq for 18 months."
The senators have different approaches to changing the way the Senate governs itself on ethics and lobbying issues. Of the 52 votes on which they differed, 22 of them involved ethics, spending priorities, and government management.
Obama favors more-extensive changes in the current system, as reflected in his vote for the creation of an independent office of public integrity to investigate possible violations of Senate rules. Clinton voted against that proposal in 2006 and 2007 -- a position consistent with that of the overwhelming majority of senators, who are leery of establishing an outside investigative entity.
"It is a centerpiece for him, and it is not a centerpiece for her," said Norman Ornstein, a resident scholar at the American Enterprise Institute who worked with Obama on the proposal and has pushed for an independent office for more than 20 years. "He handled it with a very impressive combination of real, deep-seated desire to make this happen and pragmatism about how you go about it."
The two senators have also parted company on whether illegal immigrants should have driver's licenses. Clinton initially supported New York Gov. Eliot Spitzer's move to give them that right but later reversed herself when Spitzer dropped the idea. Obama supports the proposal as a way "to protect public safety," as he said in a debate on November 15.
Still, the overwhelming consensus among political experts is that the differences between Clinton and Obama on policy are negligible. "From the perspective of most mainstream Democrats, they are not easily distinguishable on policy grounds at all," said Gary Jacobson, a political science professor at the University of California (San Diego).
Extended discussions of the two candidates' takes on various issues follows.
Domestic Policy: Economy
After a year of campaigning in which their approaches to economic policy varied significantly, Clinton and Obama are narrowing their differences.
Since delivering an economic address on February 13 in Janesville, Wis., Obama has taken some lumps from the Clinton camp -- and even from the John McCain campaign -- for appropriating several ideas that Clinton has been talking about for months. Of course, these ideas are hardly her own -- proposals for a national infrastructure bank and the creation of 5 million environmental jobs originated with Clinton's colleagues in the Senate.
But unlike Obama, who until recently avoided identifying himself with specific Democratic proposals, Clinton has long aligned herself with other Democrats. This can't be easily labeled as a centrist approach -- indeed, some of the ideas she has advocated, such as a multibillion-dollar fund to help rescue subprime mortgage holders, or a $25 billion plan to increase home-heating assistance by about 1,000 percent, are noticeably to the left of most of her colleagues' ideas.
As he comes within reach of being his party's standard-bearer, Obama is leaving behind his outsider approach and seeking common ground with other Democrats. Some proposals are strategic -- Obama has advanced more senior citizens programs than Clinton has, which might boost his standing with a group that so far has given more votes to Clinton. But on important particulars, the two call for similar things -- they would let the Bush tax cuts expire for those making more than $250,000 a year; they would expand child tax credits, the so-called marriage penalty relief, and other tax cuts targeted to the middle class. And they would depend on these changes and the benefits of bringing troops home from Iraq to pay for job-creating programs.
Except for the politically explosive issue of merit pay for teachers, not much separates Obama and Clinton on education policy. Both senators have attacked President Bush's No Child Left Behind education law as underfunded, punitive, and unnecessarily rigid. Clinton, who voted for the original law, now pledges to "get rid of" it entirely. Obama has praised its goals but called for substantial revisions.
Both candidates support charter schools, a stance that does not endear either to the politically powerful teachers unions -- although it was Obama who raised eyebrows at last July's National Education Association conference by declaring that teachers whose students excel should be paid more. But he was quick to distance himself from the idea of tying higher pay to "some arbitrary test score" -- a nonstarter with the teachers unions, whose organizing muscle is crucial to Democratic get-out-the-vote efforts -- and to proclaim his support for collective bargaining. Instead, his "Career Ladder" initiative would use a variety of assessments, including higher degrees or mentoring other teachers, to identify successful teachers.
Clinton limits her support of merit pay to rewarding entire schools whose students improve their academic performance rather than individual teachers. Like Obama, she backs financial incentives for teachers who work in difficult schools or whose subject areas need more teachers. Both have also called for higher salaries for all teachers.
Clinton and Obama stress the importance of early-childhood education, particularly for poor children. Clinton, who worked for the Children's Defense Fund early in her career and helped create the Early Head Start program, has made universal pre-kindergarten a central component of her education agenda. Obama has focused on improving the nation's middle schools and creating yearlong "residency" programs to get good teachers into struggling schools. He has also urged the creation of "innovation districts" to fund reform-minded school districts.
Similar shades of gray distinguish their higher-education platforms, both of which emphasize more money for financial aid and feature tuition tax credits paid for by eliminating the federal student-loan program that subsidizes private lenders, and other measures to hold down college costs. One of Clinton's focal points is providing support for nontraditional students and courses of study with programs to aid working adults who want to go back to school, volunteers for national service programs, and new parents. She also proposes incentive grants for colleges to improve their graduation rates, especially among poor and minority students.
Clinton has more detailed proposals to cut high school dropout rates, to reach at-risk youth, and to give students alternative paths to earn their diploma -- or pursue apprenticeships and job training. Obama has been more thematic, speaking about combating hopelessness in minority communities and holding parents accountable for their children's education.
When it comes to making big changes in the health care system, Obama is all about emphasizing the similarities between his plan and his opponent's. Clinton, however, is putting a spotlight on their one big difference.
It all comes down to so-called individual mandates. Clinton would require every person to buy insurance; Obama would impose such a mandate only on parents to purchase coverage for their children. Obama says that his goal is to achieve universal coverage by 2012 by making insurance so affordable that people would buy it voluntarily.
Both candidates say that their plans would cover everyone -- a goal that Democratic voters list as a priority -- but economists vary in their assessments, and industry groups haven't yet weighed in. Although some economists agree with Obama's assertions of universal coverage, others estimate that his plan would leave 8 million to 20 million people without insurance; and Clinton's proposal stands to leave 1 million to 2 million uncovered. Currently, 47 million Americans lack health insurance.
"If you don't have an individual requirement within the context of shared financing responsibility, you won't cover every American," said Chris Jennings, a health care adviser in the Clinton White House, who was influential in the development of Sen. Clinton's proposal. "If there's a choice, 15 million people will choose not to buy it, regardless of how much they're charged."
David Cutler, Obama's health care adviser and an economics professor at Harvard University, and Austan Goolsbee, Obama's economic adviser and an economics professor at the University of Chicago, say that his health care plan would get insurance to just as many people. "You have to make health insurance affordable and available, and if you make it that, people will buy it, and if you don't, people won't buy it," Cutler said.
The mandate isn't the only difference between the two plans. Obama, for example, would provide extra help to employers and their workers by having the federal government reimburse them for some "catastrophic" health costs, as long as the money is used to reduce workers' premiums, and he would lay out more money to help doctors and hospitals adopt electronic records systems. Clinton, for her part, proposes to limit health insurance premiums to a yet-to-be-defined percentage of family income.
Overall, many health care experts see strong resemblances between the plans. "Both have a goal of universal coverage. Both have a philosophy of shared financial responsibility. Both have employers contribute to coverage," said Karen Davis, president of the Commonwealth Fund.
Obama and Clinton also both propose generous subsidies to help low-income people buy insurance, and under their plans insurers could not deny coverage because of factors such as pre-existing medical conditions. People could continue to get coverage through employers, if they wish, or they could go to a connector-type entity and choose from a list of private health plans, plus a government-sponsored plan modeled after Medicare or the federal employees' plan.
Should Clinton fail to win the nomination, her stumble last October over the issue of driver's licenses for illegal immigrants may be pegged as the beginning of the end of her supposedly inevitable march. Asked during the Democratic debate in Philadelphia in Philadelphia whether she backed New York Gov. Eliot Spitzer's controversial move to allow illegal immigrants to obtain driver's licenses, Clinton appeared to flip from rejecting the idea to endorsing it. Obama said he supports the policy as a matter of public safety. It wasn't until the next debate two weeks later that Clinton clearly stated her opposition -- putting her in the mainstream of public opinion and setting her apart from her Democratic rival, but reinforcing the stereotype of her as a calculating politician who will say anything to get elected.
Clinton and Obama also disagree over the temporary-worker program proposed in the immigration bill that imploded on the Senate floor last summer. Clinton has echoed labor unions' concerns that it would exploit so-called guest workers and drive down wages for American workers, and she opposed it altogether. Obama called the proposed program flawed but said it should be fixed rather than scrapped. To that end, he offered an amendment to strengthen a requirement that temporary jobs be offered at prevailing wages to Americans before being opened to guest workers.
Both candidates supported every other major component of the Senate bill -- a path to citizenship for the approximately 12 million illegal immigrants now in the country, tougher border security, a requirement that employers verify that their workers are legal, and retaining family reunification as the foundation of the immigration system. Both also back the so-called DREAM Act, which would provide a route to citizenship for high school graduates or military members who were brought to the United States illegally as children. Both senators voted to increase security on the southern border with advanced technology and more than 700 miles of fencing.
In the rare cases when Clinton and Obama have cast opposing votes on the Senate floor, one subtle pattern has emerged. Clinton has voted more often to uphold traditions of the Senate, while Obama has voted to upend them. For example, Clinton has twice sided with a majority of senators to reject Obama's push to create an independent office to review ethics complaints against senators. She would instead maintain the current Senate Select Ethics Committee process. In 2006, Clinton voted with most senators for a package of modest lobbying reforms. Obama -- joined by Sens. Russell Feingold, D-Wis., and John McCain, R-Ariz. -- voted against them on the grounds that they were too weak.
On spending and earmarks, the two also found themselves on different sides on several occasions. On six occasions when Obama sided with spending hawks intent on slashing earmarks and specific projects favored by key senators, Clinton voted for senatorial courtesy and supported them. Clinton backed earmark changes that Obama opposed just twice. But both have secured earmarks for their home states -- Clinton more so than Obama, given her seniority and position on the Senate Armed Services Committee.
Obama has publicly disclosed his earmark requests for last year, a move pushed by anti-earmark groups, but neither Democrat gets as many kudos from such groups as does McCain, who does not seek earmarks and has actively worked against them.
Still, revamping the way Washington works has been a central theme of Obama's legislative effort. While Clinton has worked within the system to pass legislation on issues ranging from national security to health care, Obama has sought to change the system, most notably with two pieces of legislation: a measure that created a website listing all government contracts and grants, and ethics and lobbying legislation that was ultimately signed into law in September.
On the campaign trail, Obama points to that work as a key distinction. "I have a consistent track record of reforming government so that it's more accountable to you, the American people," Obama said on February 10 in Alexandria, Va. "Senator Clinton does not have that track record. And I don't think we can change Washington unless we can change how business is done in Washington."
Activists on ethics and lobbying issues agree that Obama was a real legislative force, along with Feingold, spurring the Senate last year to adopt tougher new rules than the chamber otherwise might have, particularly on disclosure of lobbyist campaign contribution bundling and revolving-door provisions. "He led the fight in the Senate for that bundling disclosure provision, and did it over objections and resistance in his own party," said Fred Wertheimer, president of Democracy 21, a nonprofit group.
Obama does not take money from registered lobbyists; Clinton does. But other than Clinton's opposition to the independent ethics office, activists generally regard her as a supporter of ethics and lobbying reform. Both senators, for example, back greater public financing of presidential and congressional campaigns. "I don't know that Clinton and Obama differ radically on the issue, but he has been more outspoken on it," said Melanie Sloan, executive director of Citizens for Responsibility and Ethics in Washington.
Clinton has challenged Obama's purity on ethics and lobbying issues, arguing that his decision not to take money from registered lobbyists doesn't stop him from taking money from the interests that those lobbyists represent. She has also argued that she is every bit as ethical as Obama. "If you are someone like I am, who has withstood the full force of corporate lobbyists, starting with the health insurance companies, and the drug companies, and the oil companies, and everybody that I've taken on for all of these years, you know, I think I'm independent and tough enough to be able to deal with anybody," Clinton said at a January 21 debate in South Carolina.
Foreign Policy: America's Role in the World
The defining sound bite on how the two candidates might differ about America's role in the world came on July 23, 2007, during the fifth Democratic debate. The candidates were asked, "Would you be willing to meet separately, without precondition, during the first year of your administration, in Washington or anywhere else, with the leaders of Iran, Syria, Venezuela, Cuba, and North Korea, in order to bridge the gap that divides our countries?"
"I would," Obama responded. "And the reason is this, that the notion that somehow not talking to countries is punishment to them -- which has been the guiding diplomatic principle of this administration -- is ridiculous."
Clinton, in contrast, answered: "I will not promise to meet with the leaders of these countries during my first year.... I will promise a very vigorous diplomatic effort, because I think it is not that you promise a meeting at that high a level before you know what the intentions are."
Both campaigns swept into spin mode after the debate. Clinton called Obama's remarks "irresponsible and frankly naive," and her campaign circulated a memo that turned Obama's willingness to meet with the world's worst dictators during his first year in office into a commitment to meetings with those leaders, an assertion that Clinton pressed again in the run-up to Super Tuesday. Obama, for his part, said that Clinton's approach to diplomacy represented a "continuation of the Bush-Cheney diplomatic strategies" of not talking to leaders we don't like; the Bush-Cheney comparison has since become a standard part of his repertoire.
In reality, though, Obama didn't promise meetings with anyone, and Clinton didn't reject them. Both say they would pursue diplomacy more intensively than the Bush administration has done, although Obama emphasizes his personal engagement while Clinton stresses first pursuing lower-level talks.
Take Iran. The November National Intelligence Estimate aside, that country is still apparently working on enriching uranium as well as funding terrorist groups and rattling its neighbors. Both candidates say that they would launch aggressive diplomatic tracks, offering Iran both carrots and sticks to change its behavior. Obama says he would talk directly with Iran. Clinton, who has been forced to defend her September vote in favor of labeling the Iranian Islamic Revolutionary Guard Corps a "terrorist organization," talks about "vigorous diplomacy." If Iran continues to pursue the bomb, neither one has said he or she would take the military option off the table.
Pakistan burst into the presidential campaign in August, when Obama said he was willing to pursue Qaeda figures inside that country. "If we have actionable intelligence about high-value terrorist targets and President [Pervez] Musharraf won't act, we will," he said. Clinton criticized his remarks, saying that "you shouldn't always say everything you think if you're running for president, because it has consequences across the world." On the other hand, she has also said that, in the event of actionable intelligence on a high-value terrorist in Pakistan, she, too, would ensure that he was "killed or captured."
Both candidates say they would work in their first terms to end nuclear programs in Iran and North Korea, as well as negotiate reductions in U.S. and Russian nuclear stockpiles, push ratification of the nuclear test ban treaty, and secure loose nuclear materials. Both say they endorse the vision of a world free of nuclear weapons, although their campaign advisers disagree on whether the two are saying the same thing. Obama's advisers say that while he would not unilaterally disarm, the eventual global elimination of nuclear weapons would be a driving principle of his nuclear strategy and not hers; her advisers say that she, too, is committed to taking practical steps toward accomplishing that vision.
Most of their foreign-policy disagreements, though, are rhetorical, not substantive. "There's a certain degree of looking for atmospherics to articulate differences," said Walter Russell Mead, the Henry A. Kissinger senior fellow for U.S. foreign policy at the Council on Foreign Relations. Neither candidate wants to enter the White House with his or her hands bound from the campaign. Iran, after all, doesn't have to respond to American overtures. It could, for example, instead decide to support a Hezbollah attack on American diplomats in Lebanon, in which case the president would want a full range of options on the table. "The reality is, anything they say now is hypothetical," Mead said.
Despite their bickering over the launching of the Iraq war -- he spoke against it, she voted for it, although she says if she knew then what she knows now she wouldn't have -- the two Democratic candidates hold similar positions on ending the war. Both would do so swiftly; neither would do so completely.
Obama says he would withdraw all combat brigades from Iraq within 16 months. Clinton says she would start pulling the first brigades out within 60 days; in December, she told The New York Times that she thought "nearly everybody" could be home within a year.
Both candidates, however, say that some troops would remain in Iraq to protect American diplomatic and military personnel; to target Al Qaeda in Iraq; and, with caveats about Iraq's political circumstances, to continue training the Iraqi army and security forces.
In practice, accomplishing the candidates' more limited goals in Iraq would still mean leaving anywhere from 10,000 to 75,000 troops in Iraq, or more. It currently takes more than 100,000 military personnel, and an equal number of contractors, to fulfill those same three missions in Iraq, according to a rough count by Anthony Cordesman, the Arleigh A. Burke Chair in strategy at the Center for Strategic and International Studies. Both candidates have indicated they would like to reduce America's footprint in the country and use air and special operations teams to carry out strikes on Al Qaeda in Iraq, but Cordesman says that that notion is virtually meaningless until the Iraqi army and security forces are ready to stand on their own. "We'd kill some cadres but have little or no overall impact, and we'd lose almost all of our [human intelligence] once we withdrew," he said.
Obama and Clinton have both shied away from questions about just how many troops would remain in Iraq under their plans. "They don't want to get pinned down," said an Obama adviser, describing the two candidates. Their deliberate vagueness could, if they reach the White House, leave voters with a bad taste in their mouths, similar to that expressed for the current Congress's failures to end the war. "There's a potential for backlash there," the adviser said.
On February 19, when Fidel Castro announced that he was stepping down as Cuba's president, Obama and Clinton issued similar statements that belied the differences in their Cuba policies. Both said that if the new Cuban government took serious steps toward democracy, the U.S. would be prepared to meet it.
In August 2007, Obama broke with the current policy on Cuba by saying that he would grant Cuban-Americans unrestricted rights to pay visits, and send money, to their families still in Cuba. A 2004 change by the Bush administration had limited Cuban-Americans to one 14-day island visit every three years to members of their direct family (defined as grandparents, parents, siblings, spouses, children, and grandchildren), and $300 in quarterly remittances to the households of their direct family members. (The previous policy had allowed one visit every 12 months and up to $3,000 in remittances a year.) "Cuban-American connections to family in Cuba are not only a basic right in humanitarian terms but also our best tool for helping to foster the beginnings of grassroots democracy on the island," Obama wrote in a Miami Herald op-ed.
In response to Obama's proposal, one of Clinton's campaign spokesmen told Herald reporters that Clinton "supports the embargo and our current policy toward Cuba."
Clinton's actual position is a little more nuanced than her support for "current policy" would indicate. She does in fact support a more flexible policy for families' humanitarian travel to the island. She has not, however, taken a formal position on the remittance restrictions. In general, Clinton argues that "wholesale or broad changes to our Cuba policy, including the embargo," should wait for "changes and fundamental reforms" in Cuba, as she wrote in a candidate questionnaire administered by the Cuban American National Foundation.
Easing the Bush restrictions is popular with those Cuban-Americans who have arrived recently. The older generation, though, which came to the U.S. immediately after the 1959 Cuban revolution, tends to support the stricter policies, according to a survey conducted last year by the Institute for Public Opinion Research and Florida International University.
"If whomever the next president is lifts the travel ban and restrictions on remittances for Cuban-Americans, the Spanish language radio stations in Miami would have a field day," said Marifeli Perez-Stable, the vice president for democratic governance at the Inter-American Dialogue. "But we have poll data that consistently shows Cuban-Americans, particularly those who arrived in the 1980s and 1990s, want to go see their families." The older generation, she said, generally doesn't have much family remaining in Cuba; on the other hand, that first wave of exiles tends to constitute the majority of Cuban-American voters.
Staff Correspondents Corine Hegland, Brian Friel, Marilyn Werber Serafini, Lisa Caruso, Margaret Kriz, Bruce Stokes, and John Maggs contributed to this article.