After winning 11 straight primary and caucus victories against New York Sen. Hillary Clinton, Illinois Sen. Barack Obama, the current Democratic front-runner in the race to the White House, appears to be encroaching on Clinton territory in Ohio and Texas.
The most recent ABC News/ Washington Post poll showed him closing in on Clinton's once hefty lead in both states, and polls conducted since show an even tighter race.
Clinton has also received pressure from prominent Democrats and Obama backers to withdraw if she does not perform well in Texas and Ohio, Tuesday.
"Well, I think that'll be up to Sen. Clinton," said Obama. "But if we do well in Texas and Ohio, I think the math is such where it's going to be hard for her to win the nomination, and they'll have to make a decision about how much longer they want to pursue it."
"I would assume that there are going to be people who want to bring this to an end one way or another, because [Arizona Sen.] John McCain's out there — the reputed Republican nominee — and he's given a little bit of a free pass."
Huge crowds greeted Obama in Westerville, Ohio, Sunday. There was a decent amount of overflow and a few hundred left outside, unable to squeeze in.
Earlier in the day, a smaller event took place in the outskirts of Appalachia where he talked up "green jobs," but told the small audience it would be a challenge to turn the economy around.
To many political experts, Clinton's performance in delegate-rich states like Ohio and Texas has the potential of deciding the future of her campaign. Even former President Clinton has admitted that losing one could mean the end of his wife's presidential run.
Obama says he's not taking any chances. "Remember New Hampshire," he reminded reporters last week, recalling his surprising defeat in the New Hampshire primary.
But Clinton, feeling a newfound surge in energy after raising more than $35 million in February — Obama has reportedly raised more than $50 million — has shown no signs of giving up.
Recently, the Clinton campaign has increased its attacks on Obama, and the candidate has kicked up her rhetoric.
"For some people, this election is about how you feel," she told a crowd at a rally in Westerville, Ohio. "It is about speeches. That is not what it is about for me. It is about solutions."
Clinton sparked media attention last week after her campaign aired a new ad in Texas that suggests the senator is better able to handle a national crisis.
"It's 3 a.m. and your children are safe and asleep," a deep, ominous voice explains in the ad, while a camera pans over the faces of sleeping children. "But there's a phone in the White House, and it's ringing. Something's happened in the world. Your vote will decide who answers the call."
The Obama campaign accused the Clinton campaign of "fear-mongering."
"I think she has got a little desperate toward the end of this campaign," Obama told "Nightline's" Terry Moran, while campaigning in Ohio. "[She] has been a lot more aggressive in her negative attacks.
"As I've pointed out, we've actually had a pretty significant moment in the last several years, that called people's judgment into question. And that was the war in Iraq."