For weeks, Hillary Clinton's campaign has argued that it would be  irresponsible—reckless, even—for Democrats to nominate Barack  Obama because he hasn't endured enough scrutiny. So i n the days ahead of the Wisconsin vote, the Clinton campaign stepped up its attacks, unleashing several negative TV  ads against Obama . Clinton aides also successfully pushed two days of news coverage suggesting that Obama had "plagiarized" a couple  of lines from his campaign co-chair, Deval Patrick, the Massachusetts  governor.

Nothing stuck. According to exit polls, Obama won big among men and drew almost  even among women in Wisconsin. He won among lower-wage earners, who were Clinton's most reliable supporters  less than a month ago. And he drew even among high-school graduates, 
while still maintaining his support among higher-earners and those  with college degrees. Clinton won among white Democrats, but lost  heavily among independents; she won seniors, but lost older, middle- aged voters that have previously swung behind her.

Perhaps most striking was that Obama erased Clinton's two strongest  poll advantages over the course of the last year of campaigning. On  the issues of electability and the qualifications to be commander-in- chief, Obama beat Clinton in the exit polls.

Wisconsin was supposed to be the kind of state that was perfect for  Clinton: predominantly white, it has plenty of blue-collar workers who  should have appreciated her focus on economic issues. Recent polling  in the state suggested the state was entirely winnable for Clinton. Coming out of Super Tuesday, Obama's lead was in the low single- digits. One recent poll gave Clinton a 6-point lead, while two others  gave Obama a double-digit lead.

But the Clinton campaign seemed torn over whether to fight in Wisconsin as a way of halting Obama's Super Tuesday momentum, or simply concede another state—and wait another two weeks until Texas and Ohio. Clinton cut back on her  travel to Wisconsin but increased her ad spending there.

She and her aides also moved to attack Obama on an almost daily basis,  especially taking aim at Obama's ability to deliver inspiring speeches  by questioning his authenticity. Having pushed the "plagiarism" story  hard in the closing days of the Wisconsin primary, the Clinton  campaign then took the rare step of thanking the media. "Look, it's not  us making this charge. It's the media," Hillary Clinton told Honolulu  TV on Tuesday. "You know, the media is finally examining my opponent  which I think is important because we're trying to pick a president,  someone for the toughest job in the world."

For Obama's aides, the Wisconsin victory was proof that they could  sustain and thrive in the face of aggressive campaigning. "I think  they rejected the negative attacks," said Obama's senior strategist  David Axelrod. "It looks like a fairly significant win in a state  where the demographics were actually pretty good for her. We won among  late deciders, which tells me the negative campaign didn't work."

For Obama's supporters at a Tuesday night rally in Houston,  the Wisconsin victory only added to their enthusiasm. The 20,000- strong crowd in the Toyota arena would barely allow Obama to speak  when he emerged on stage. "Houston," he said, "I think we have  achieved lift off."

Still, this was no ordinary victory speech. Obama dispensed with his  scripted oratory, and the autocue screens, to start with some voter  mobilization. Given the intricacies of Texas voting, the Democratic  campaigns need to get their supporters to vote in both a primary and a 
caucus on the same day. Obama went one step further by urging his  crowd to vote early, and then attend the caucus on March 4.

But most of all, he urged his supporters to be ready for an extended  fight—beyond the convention and even the general election. "The  change we seek is still months and miles away and we need the good  people of Texas to help us get there," he said. "We will need you to 
fight for every delegate it takes to win this nomination. And if we  win the nomination, if we are honored to win the nomination, we are  going to need your help to win in November. And if we win that  election in November, then we are going to need your help and your  time and your energy, your enthusiasm, your mobilization, your  organization and your voice to help us change America for the next  four years."

With several weeks of campaigning ahead of him—and several victories  behind him—Obama shows no sign of relaxing into the frontrunner's  position any time soon.