Hillary Clinton stopped Barack Obama’s winning streak cold last night by winning three out of four primaries, including a big win in Ohio and a surprising win in Texas. The momentum from these victories will undoubtedly propel her all the way to Pennsylvania, and almost certainly to the convention in Denver. But did last night really affect the delegate chase at all? The Washington Post analysis sounds pessimistic:

Critical to Clinton’s prospect of victory are the superdelegates, the nearly 800 elected officials and party leaders who can vote any way they choose. Her campaign envisions what aides call a “buyer’s remorse” strategy of raising enough doubts about the first-term senator from Illinois through increasingly vigorous attacks and tougher media scrutiny to convince the superdelegates that it would be too risky to nominate him.

That reflects the recognition that it would be enormously difficult for Clinton to overtake Obama in the pledged delegates chosen by voters in primaries and caucuses. By some calculations, Clinton would need to win more than 60 percent of the vote in the dozen contests remaining between now and June 7 to catch Obama in pledged delegates — a steep challenge given that, so far, she has won that much in only one state, her onetime adopted home of Arkansas. Even in New York, where she is a sitting senator, she won 57 percent of the vote. She won 55 percent in Michigan, where Obama was not even on the ballot.

“Her durability is impressive if not astonishing, but she is still looking at some pretty cold, hard numbers in the race,” said Jim Jordan, a Democratic strategist who initially ran the 2004 primary campaign of Sen. John F. Kerry (D-Mass.). “She’s running out of time, she’s running out of space.” He described a Clinton nomination even with wins in Texas and Ohio as “impossible, really.”

Steve McMahon, another Democratic strategist who is not working for either candidate, said the odds are long. “It’s difficult to see how the math works for Senator Clinton,” he said. “If you look at most models out there circulating, the one thing that’s consistent is that she has to perform pretty strongly in order to have any hope of making up the deficit among elected delegates.”

Mathematics aren’t really the issue here. She has pulled back to within 100 pledged delegates of Barack Obama with her victories last night. Even the Texas caucus, which everyone expected her to lose, looks razor-thin. After small contests in Wyoming and Mississippi, she can eye the 188 delegates in Pennsylvania and hope to gain some ground there as well.

Her triumph last night had little to do with numbers and everything to do with appearances, however. Obama has begun looking invincible, but Hillary managed to stop him, even after she slid out of the lead in Texas. Thanks to the twin gifts of the Rezko trial and the NAFTA dance, Obama not only started facing a few tough questions from the media, he blew up when they asked them of him. Hillary went negative to keep the pressure on him, and Obama displayed a glass jaw.

That will have the superdelegates — the party establishment — wondering whether Obama is ready for prime time. And now that question will occur not in the context of an overwhelming, unstoppable movement, but in the context of Hillary victories that indicate the party wants this race to continue. Hillary’s team will sell this as a vote of non-confidence; Texas and Ohio had the opportunity to climb on the Obama bandwagon and rejected it.

And if the electoral circumstances have changed, the superdelegates may decide that they have the freedom to ignore the popular vote results and vote for the better candidate. That has been the aim of Team Hillary for the last two weeks: to reverse the dynamic developing among superdelegates to follow the popular vote. If she takes Pennsylvania and Indiana, she may convince them that Obama just doesn’t have what it takes to survive a long, grueling race against John McCain, and she could win the nomination while trailing Obama in pledged delegates.

If she stays close — within 100 delegates — the argument practically makes itself now. Denver will become a massive battleground, and the nomination could be within her grasp, especially if the Rezko trial produces something unexpected.