Winning three out of four primaries up for grabs last night, Sen. Hillary Rodham Clinton of New York gave her presidential campaign a new lease on life.

After struggling through much of February -- and 11 consecutive primary and caucus losses to her rival, Sen. Barack Obama of Illinois -- Clinton roared back to capture the Ohio, Rhode Island and Texas primaries. Obama's lone victory in the March 4 contests came in Vermont which, as expected, he won handily.

	People who said they made up their minds about which candidate to vote for three days before the primary chose Clinton overwhelmingly in Ohio and Texas.

Before the primary day balloting, Clinton campaign strategists asserted that if she could stop Obama's momentum, it should be interpreted as a vote of confidence for her in two key areas: managing the economy and serving as commander in chief. The campaign hammered those themes in Ohio and Texas, respectively, and the results of the National Election Pool exit poll for the Democratic primary (conducted by Edison Media Research and Mitofsky International for AP, ABC, CBS, CNN, FOX and NBC) suggest they worked.

In Ohio, 59 percent of Democratic primary voters said the economy was the most important issue facing the country; 55 percent of those voters backed Clinton, while 43 percent sided with Obama. In Texas, where the Clinton campaign ran a "Red Phone" television ad (subscription) asking voters who they wanted picking up the line, the message apparently got through. When voters were asked who they thought was more qualified to be commander in chief, 56 percent chose Clinton and 38 percent picked Obama.

But Obama's problems extended beyond those two issues. He had an uncharacteristically bad spate of media coverage, which included the opening of a corruption trial against a former fundraiser and a bungled response to questions about a campaign adviser's meeting with Canadian diplomats in Chicago. People who said they made up their minds about which candidate to vote for three days before the primary -- when the Clinton campaign was fanning those two stories -- chose Clinton overwhelmingly in both Ohio and Texas.

With nearly all the state's precincts reporting in Ohio, Clinton defeated Obama 55 percent to 45 percent. Her victory was more modest in Texas, roughly 51 percent to Obama's 47 percent. In Rhode Island, Clinton trounced Obama by about 58 percent to 40 percent. Obama led Clinton in Vermont with 86 percent of the precincts reporting, 60 percent to 38 percent.

White Men & Swing Voters Help Clinton In Ohio
Clinton's Ohio victory was particularly heartening for her campaign, coming off a loss to Obama two weeks earlier in Wisconsin that some observers thought might be a harbinger for her in the Buckeye State. But in Ohio, she was able to neutralize some of Obama's core supporters and capture some swing-voter blocs.

The NEP exit poll found that in Ohio, Clinton won white men -- now a swing vote in the Democratic primaries -- 58 percent to 39 percent over Obama. Obama had carried white men by a bigger margin in Wisconsin, 63 percent to 34 percent.

Rural and small town voters, another swing group, swung solidly to Clinton in Ohio. She swamped Obama in this group of voters, 70 percent to 26 percent. In Wisconsin, Obama won the small town-rural vote, 57 percent to 41 percent.

Winning large margins among independent voters has been a key factor in most of Obama's victories over Clinton this year, but he lost that advantage on Tuesday. Clinton held Obama to 50 percent of the independent vote in Ohio, while she won 48 percent. And among white independents who voted in the Ohio Democratic primary, Clinton edged out Obama to capture 53 percent to his 45 percent. In Wisconsin, Obama had taken white independents handily, 62 percent to Clinton's 35 percent.

Obama won four of the top five vote producing counties in the Ohio primary -- Cuyahoga, Franklin (Columbus), Hamilton (Cincinnati) and Montgomery (Dayton) -- but Clinton swept much of the rest of the state. She ran very strongly in the southeast, the political base of Ohio Gov. Ted Strickland (D), who endorsed Clinton and was constantly at her side campaigning. She captured the declining industrial centers in northeastern Ohio like Summit County (Akron), Mahoning and Trumbull counties (Youngstown) and Stark County (Canton). She also handily won the northwestern corner of the state dominated by Toledo.

All told, Clinton won at least 82 of the state's 88 counties. Obama won five counties, including Delaware, the fast-growing exurban territory north of Columbus, but they were in the state's urban centers. One small county, Darke, had not reported any results as of 7 a.m. today.

Texas & The Latino Vote
In Texas, Clinton's victory was largely due to the overwhelming support she received from Hispanic and Latino voters. Obama strategists in Texas felt he had to win roughly two out of every five voters in this group to carry the state, but he fell far short of that goal; Clinton won Latinos by more than a two-to-one margin, 67 percent to 31 percent. Her strongest geographic region in the state was the traditional Hispanic political stronghold in South Texas and Rio Grande Valley -- an area in which both she and her husband, former President Bill Clinton, stumped repeatedly.

The Hispanic turnout beat turnout among African-American voters: The former made up roughly 34 percent of the Democratic primary electorate, while the latter accounted for some 19 percent.

Clinton also ran strongly in rural West Texas, as well as the part of the state that lies south of Arkansas.

According to the Texas Secretary of State's office, Obama narrowly won the absentee and early vote by 51 percent to 48 percent. And he ran very strongly in the urban centers of Austin, Houston and Dallas-Fort Worth, where his campaign increased turnout and the share of the statewide vote. But that was not enough to overtake Clinton in the rest of the state.

She carried white men with 50 percent to Obama's 47 percent -- not nearly the same big margins as Ohio. But her support among white women was resounding: 60 percent compared with 39 percent for Obama. She and Obama essentially split independents, including white independents, overall. Among voters in rural areas and small towns, Clinton won 61 percent to Obama's 36 percent.

The Small Fries
In Rhode Island, which Clinton won handily, women and Catholics were keys to her victory. She and Obama split the male vote, but Clinton won women 2 to 1 -- and women made up 57 percent of the primary electorate. Clinton also carried Catholics, who made up 55 percent of the primary vote, by a 2-to-1 margin.

Conversely, in Vermont, Obama's core supporters stuck by him and swing voters sided with him. Independents in the Green Mountain State cast their primary ballots for Obama by almost a 2-to-1 margin. At the same time, Obama carried white men with 64 percent to Clinton's 35 percent.

Huckabee Bows Out As McCain Ascends
And as the Democratic race was opening a new chapter, the Republican presidential contest came to a close. Sen. John McCain of Arizona easily won all four primaries over former Arkansas Gov. Mike Huckabee, and McCain was able to claim the GOP nomination. In his concession speech, Huckabee withdrew from the presidential race.

-- See NationalJournal.com's Campaign Tracker for more election coverage.