Extending his winning streak, Sen. Barack Obama, D-Ill., has defeated Sen. Hillary Clinton, D-N.Y., in the Hawaii and the Wisconsin Democratic primary, with high support among independent voters, and eating into her support among key Democratic voters.
"Houston, I think we have achieved liftoff here!" Obama said at a victory rally in Houston, Texas Tuesday night.
Voters Say Obama More Electable
They were decisive victories for Obama, racking up 58 percent of the vote to Clinton's 41 percent in Wisconsin, and clobbering her in his native Hawaii 75 percent to her 24 percent.
Wisconsin Democrats identified Obama, not Clinton, as most likely to win in November, according to preliminary exit poll results.
Yet another primary contest loss was another blow to Clinton, who struggled to hold on to the support of some of her core groups — white women, less-educated and lower-income voters — while Obama enjoyed sweeping support among younger voters, winning whites under 30 by his biggest margin to date, according to exit poll results.
At a rally in Youngstown, Ohio, Clinton didn't acknowledge her defeat in Wisconsin, instead sharpening the contrast between her and Obama's candidacy.
"They need a president ready on day one to be commander in chief, ready to manage our economy, and ready to beat the Republicans," Clinton said.
"It is about picking a president who relies not just on words — but on work, on hard work, to get America back to work," she said. "That's our goal. We can't just have speeches, we've got to have solutions and we need those solutions for America. We've got to get America back in the solutions business."
McCain Rips Obama
Republican front-runner Sen. John McCain, R-Ariz., moved yet another step closer tonight toward securing the GOP nomination, defeating former Gov. Mike Huckabee, R-Ark., and Rep. Ron Paul, R-Texas, in the Wisconsin Republican primary. McCain had 55 percent of the Wisconsin GOP vote.
McCain also picked up delegates in the Washington State GOP primary. The Democratic primary in Washington was considered a beauty contest -- delegates had been awarded two weeks ago when Obama won the state's caucuses.
On Wednesday's "Good Morning America" McCain slammed Obama, arguing he is better-suited to handling national security issues.
"Senator Obama wants to bomb Pakistan without talking to the Pakistanis, I think that's dangerous. So I think that that's an important factor, experience in judgement, and ready to serve, and no on-the-job-training."
In Wisconsin, McCain made progress in wooing conservatives skeptical of his record, splitting them evenly with Huckabee, according to preliminary exit poll results. McCain also won four in 10 voters who describe themselves as very conservative, his best showing so far. However, Huckabee, a former Baptist minister, held onto his advantage among Christian evangelicals, winning them by 20 points, according to preliminary exit poll results.
With his wife Cindy standing by his side, McCain took a swipe against Obama Tuesday night, in a victory speech focused on the fight against terrorism.
"I will work hard to make sure Americans aren't deceived by an eloquent, but empty call for change," McCain said.
The presumed Republican nominee also knocked his likely Democratic opponent by taking a shot at the "confused leadership of an inexperienced candidate."
McCain also took a subtle dig at Obama's wife, Michelle.
"I have never lived a day, in good times or bad, that I haven't been proud of the privilege" of being an American, McCain said.
Michelle Obama has been criticized for saying, in Milwaukee, Wis., Monday, "For the first time in my adult lifetime, I'm really proud of my country and not just because Barack has done well, but because I think people are hungry for change."
In a rare move, Cindy McCain, wife of the Arizona senator, took on Michelle Obama's comment: "I'm proud of my country, I don't know if you heard those words earlier. I'm very proud of my country," she said Tuesday.
Tuesday's biggest prize was the economically struggling state of Wisconsin, which has 74 Democratic delegates at stake, and bragging rights to a state with a sizable population of blue-collar workers.
Obama's campaign argued a win in Wisconsin would quiet opponents who credited his past victories to black voters, highly educated, and high-income Democrats.
In the end, the Illinois senator challenged Clinton in some of her core support groups, trounced her on electability, and rode broad support from independents to victory in the state.
Clinton held only a single-digit lead among white women, according to exit poll results. Obama, meanwhile, prevailed by a wide margin among men.
The most striking result was Obama's huge victory among a high turnout of voters under 30; he won them by 71-25 percent.
In his speech tonight, Obama pushed back on the criticism that he is all talk and no substance.
Ohio, Ohio, Ohio
Clinton's campaign has been busily lowering expectations in Wisconsin, and the candidate left the state Monday, preferring to hold events in Ohio.
The former first lady clearly wants her campaign — and the media — to focus on the next-up primary contests on March 4 in delegate-rich Ohio and Texas, but she did spend significant time and resources in Wisconsin.
Clinton wooed blue-collar workers with a detailed economic plan, and sent negative mailers to voters, arguing Obama's health care plan would leave millions uninsured.
The Clinton campaign also launched its first negative television ad in Wisconsin, attacking Obama in an effort to highlight his refusal to debate her in the state.
Former President Clinton and daughter Chelsea also pitched in, visiting universities and holding town hall meetings.
Publicly, the Clinton campaign argues it never expected to win in Wisconsin, but Clinton associates concede it's a tough night for the campaign, reports ABC News' Kate Snow.
"Obama will win tonight, but as more people focus on him as president and commander in chief, he's going to have a tougher and tougher race," Clinton spokesman Jay Carson told Snow.
"All you have to do is listen to Sen. McCain tonight to see that Democrats need to have a candidate with the strength and experience to take him on," Carson said.
Hawaii's Aloha Primary
Outside the Badger State, the Clinton campaign dispatched Chelsea Clinton to campaign for her mom in Hawaii, where 20 delegates are up for grabs.
But it was Obama, born and raised in Honolulu, who had the advantage there.
The Illinois senator's half-sister campaigned on his behalf, recording a YouTube video encouraging voters to support her brother.
Clinton Focuses on Ohio, Texas
The loss in Wisconsin is another blow to the former first lady, whose candidacy is now undeniably in jeopardy.
Obama and Clinton take their battle to Ohio and Texas, states Clinton admitted this week, will be crucial for her candidacy.
With neither candidate poised to reach the 2,025 delegates needed to win the nomination before the party's August convention in Denver, the Democratic battle has become a state-by-state fight for delegates and momentum.
Obama now holds a 94-delegate lead over Clinton, according to ABC News' delegate scorecard.
Since Obama swept the Potomac primaries last week in Virginia, Maryland and Washington, D.C., Clinton has sharpened her attacks, suggesting her opponent is all talk and no action.
Asked about a speech Obama gave last weekend in Wisconsin, in which he borrowed lines from Gov. Deval Patrick, D-Mass., Clinton didn't comment directly on the plagiarism assertion, but did suggest Obama's candidacy is about rhetoric, and little else.
"The real issue is, if your entire candidacy is about words, they should be your own words," Clinton said during a satellite interview with KGMB, the CBS affilliate in Honolulu.
"And you may know that both Deval Patrick and Sen. Obama have the same consultant and adviser, who is apparently putting words in both of their mouths," she said.
Obama argued Clinton has used lines from his speeches, too. Patrick, who has endorsed Obama, has defended his friend.
Plagiarism to Poaching
Accusations of plagiarism aren't the only themes dominating the discussion, as voters in Wisconsin and Hawaii headed to the polls.
The subject changed from plagiarism to party politics after an unnamed Clinton official told Politico that both campaigns would go after the pledged delegates if there is a stalemate between the candidates, going into this summer's Democratic convention.
On separate conference calls with reporters, both campaigns denied they plan to poach each other's pledged delegates.
The Obama campaign linked the story with the Clinton campaign's attempt to get Florida and Michigan delegates seated at the convention.
Clinton won in both states where the Democratic Party had stripped them of their delegates, as punishment for moving up their primary dates.
"The Clinton campaign has once again floated a strategy that would essentially say that the preference of Democratic voters is a mere obstacle to their win-at-all-costs strategy," Obama campaign manager David Plouffe said in an e-mail to reporters, Tuesday.
Candidates Look Ahead to Texas and Ohio
Focusing on the economy, Obama campaigned in Texas, Tuesday, while Clinton focused on Ohio, where she currently holds a strong lead in the polls.
Targeting working-class voters, Clinton launched a new ad campaign in Ohio, called "Night Shift," suggesting the New York senator can relate to the underpaid, overworked person, pouring coffee or working the night shift at the local hospital because she's worked the night shift, too.
Beginning Wednesday, Emily's List, a group that works to elect female candidates who support abortion rights, and has endorsed Clinton, will send mail and call non-college-educated women, rural women and older women squeezed by economic pressures. Using a peer-to-peer tactic, the group will use Ohio women to contact these women and urge them to vote for Clinton.
Both Obama and Clinton have adopted a populist message on the economy, and have met individually with former Sen. John Edwards in attempts to win his endorsement.
The race in Texas is tight, with Clinton and Obama essentially tied, at 50-48 percent, according to the latest CNN/Opinion Research Corp. poll.
Both candidates face off against one another in a debate Thursday in Austin, Texas, the last before voters go to the polls in Ohio, where 141 delegates are at stake, and Texas, which has 193 delegates.
The Clinton campaign has suggested the way Texas proportions its delegates may unfairly punish Clinton, who has targeted Hispanic areas that yield fewer delegates.
Ohio and Texas are now must-wins for Clinton's presidential candidacy, where she will spend the next two weeks trying to stop the undeniable momentum Obama has going into the delegate-rich contests on March 4.
"It's not going to be enough for her to win now in Texas and Ohio," ABC News' George Stephanopoulos said on Wednesday's "Good Morning America."
"In order to catch up in the delegates now she's going to have to beat him by the kind of landslides he's been beating her by."
ABC News' Gary Langer, Kate Snow, Sunlen Miller, Eloise Harper, Bret Hovell, Ron Claiborne, Teddy Davis and Kevin Chupka contributed to this report.