WESTERVILLE, Ohio — With time running out on her dream, Hillary Clinton kicked off a two-day bus tour of Ohio Sunday with a dire warning about rival Barack Obama and a plea for support from a state uniquely positioned either to breathe new life into her struggling campaign or to end it.
"We really need you," Clinton told about 3,000 people in Westerville, a suburb outside Columbus.
Turning up the heat, she pressed her argument that she alone is experienced enough to handle a crisis at 3 in the morning — backing up an emotionally charged TV ad that has reverberated, for good or ill, more than any other ad this campaign.
"When the cameras are gone, and the lights are out, the president of the United States, as I know very well, is in that White House," she said. "Yes, there are advisers. There's all kinds of people who say do this or do that. But the president has to decide.
"When those calls come at 3 am, it could be a national security crisis; it could be an economic crisis."
But Obama and his supporters fired back.
"She has supposedly all this vast foreign policy experience," Obama said at a rally just a mile from where Clinton spoke. "When it came to making what is surely the most important foreign policy decision of our generation...Sen. Clinton got it wrong" — a reference to Clinton's vote to authorize the Iraq war.
"We're still waiting to hear Hillary Clinton tell us what precise foreign policy experience she is claiming that makes her prepared to answer that phone call at 3 o'clock in the morning," he said.
Polls released Sunday gave Clinton some hope that she could prevail in Ohio on Tuesday, something many of her supporters concede she must do to keep her candidacy arrive after losing 11 contests in a row to Obama.
In Ohio, she still holds on to a slim lead of about 4 percentage points, according to a Mason-Dixon poll, though that spread is within the margin of error, meaning it might not really exist.
In Texas, the other big state to vote Tuesday, the margin is much smaller and favors Obama, according to a Mason-Dixon poll also released on Sunday.
Other polls released Sunday showed different margins, including one that gave Clinton a wide advantage over Obama in Ohio. But even Clinton staffers dismissed that poll, saying their own internal surveys show her with only a small edge.
Clinton supporters acknowledge that she must win both Texas and Ohio to have any hopes of staying in the race. Smaller Rhode Island and Vermont also vote on Tuesday.
Obama also is pouring it on, outspending her 2-1 on TV ads, hoping to deliver a crushing blow on Tuesday that will force her from the race.
Clinton's assertion that she could better handle a national security crisis than Obama, a first term senator from Illinois, dominated the debate as the campaign entered its final hours.
The issue was raised by the Clinton ad, which the Obama campaign responded to immediately with a similar ad that raised the issue of whether Clinton has the judgment to be trusted to answer the phone.
"When that call gets answered," the Obama ad said, "shouldn't the president be the one, the only one, who had judgment and courage to oppose the Iraq war from the start? Who understood the real threat to America was al-Qaeda in Afghanistan, not Iraq? Who led the effort to secure loose nuclear weapons around the globe?"
"In a dangerous world, it's judgment that matters," the ad concluded.
The Clinton approach seemed to sway some voters.
"I wouldn't want him to be the one picking up the phone, he's too inexperienced," said Mary Ellen Zoerner, a registered nurse from Lewis Center, Ohio, who said she was undecided in the race.
Others saw it as unconvincing. "That ad is just fear mongering," said Jackie Kreutzer, a retired psychologist from Upper Arlington, Ohio, who supports Obama.
"She claims to have all this experience because she was first lady," Kreutzer said. "Well, my husband was a physician and used to get calls in the middle of the night. It didn't mean I had experience."
Some professionals not affiliated with either campaign questioned whether the ad would help Clinton's chances.
"The big downside is it brought Iraq and the vote on the Iraq war right back to the middle of the stage of the campaign," Democratic strategist Robert Shrum said on NBC's Meet the Press. "And I think that David Axelrod and Jim Margolis, who were doing the media for Obama, did a very, very smart thing by focusing their response so heavily on the Iraq war and the Iraq war vote."