Two major pollsters show Hillary Clinton moving back into a national lead over Barack Obama following her big wins yesterday in Texas and Ohio. Gallup has Hillary in front by four, and Rasmussen’s daily poll has her leading for the first time in three weeks, 48-43. It also has some good news for Republican nominee John McCain after his success in clinching his spot last night:

Prior to the past three days, Clinton had trailed Obama every single day for three weeks (see recent daily results). Clinton has regained a solid lead (twelve percentage points) among women nationwide. That margin that expands to twenty points among white women. Yesterday’s victories for Clinton mean there is a growing likelihood that the campaign could stretch on in to the summer without a winner. Rasmussen Reports will be polling the Democratic Primary Race in Mississippi, Pennsylvania, North Carolina, and other states this week. …

Looking to the general election, John McCain has a slight lead over both Democrats. McCain now leads Obama 48% to 43% and Clinton 46% to 45% (see recent daily results). A Rasmussen Reports video suggests that the Clinton victories in Texas and Ohio are good news for John McCain. In Washington State, McCain leads Clinton and is essentially even with Obama.

McCain leads Hillary in Washington? The northwestern state is usually considered a safe haven for Democrats, even in presidential elections. John Kerry won Washington easily in 2004, 53%-46, while Patty Murray coasted to a 12-point re-election victory over her GOP challenger. Just being even with Obama at this point would have been an accomplishment, and shows that McCain may present a more formidable challenge than either candidate anticipates.

Earlier, Hillary claimed that her campaign turned a corner, and suggested that Obama might join her as the VP:

In an interview on CNN Wednesday morning, Mrs. Clinton said she was not deterred by Mr. Obama’s continued lead in elected delegate support, and argued that she would be the stronger candidate in a general election against the now-assured Republican candidate, Senator John McCain. “What’s important is that this campaign has turned a corner,” she said. …

In another televised interview, Mrs. Clinton said her close race with Mr. Obama might result in a shared ticket. Speaking on CBS’s Early Show, she said, “Well, that may be where this is headed, but of course we have to decide who is on the top of the ticket.” She said her victory in Ohio indicated that the choice should be her.

That’s rather bold for someone who lost ten states in a row and went just about 0 for February. Still, Texas and Ohio Democrats had an opportunity to put her away, but they kept her campaign alive instead. They didn’t do enough to change the math, however, and it seems very unlikely that Obama will lose his lead in pledged delegates before the Denver convention.

Hillary will argue that Obama proved himself a weaker candidate in the crucible of real pressure, and that he needs seasoning. She will appeal to the party establishment — the superdelegates — to vote overwhelmingly for her and to have Obama on the ticket, under the tutelage of the Clintons, in preparation for his own presidency in 2016. Undoubtedly some will find that compelling, especially if the Tony Rezko trial offers any embarrassing revelations about Obama’s relationship with the fixer.

However, don’t expect Obama to go along with that scenario. If he goes into Denver with a lead, he will expect the nomination. Anything less than that would require him to endorse a back-room maneuver that he has made the antithesis of his campaign. He simply cannot survive politically with his coalition intact with that humiliation.

If Obama doesn’t get the nomination, don’t expect him on the bottom of the ticket — and don’t expect his backers to endorse unity, either. Expect a meltdown.