Sensing the possibility of an 11th-hour reversal of fortune in her favour, a newly energised Hillary Clinton made one final tear across Ohio and Texas, urging her supporters to rally their friends and families today for what she called "a big vote for a big decision".
With the future of her presidential campaign on the line, Senator Clinton emphasised again and again that she is a fighter who won't quit now and won't quit if she ever gets back to the White House.
She was, she told cheering supporters at her final election eve rally in Austin, the Texas capital, as idealistic and determined to change the country now as she was as a 24-year-old volunteer registering Hispanic voters in South Texas in 1972. All that had changed, she said, was that she was older. "I have," she said to laughter and applause, "earned every wrinkle on my face."
The former First Lady appeared heartened by evidence that some of the mud she has spent the past week hurling at her Democratic primary opponent, Barack Obama, may at last be sticking. Senator Obama, who closed out his own campaign with a typically packed appearance three hours' drive away from her in Houston, found himself on the defensive on several fronts – fending off accusations that his campaign had privately told the Canadian government not to take his populist anti-free trade rhetoric too seriously, and distancing himself from a former donor, Chicago property developer Tony Rezko, who went on trial yesterday on political corruption charges.
He has also had to answer charges that he isn't seasoned enough to handle a full-blown national security crisis – the subject of a controversial Clinton scare advert featuring sleeping children and a phone ringing in the middle of the night – and battle against a long-standing rumour that he is Muslim. (He is in fact a practising Christian.)
As much as possible, Senator Obama has sought to turn the accusation back on his attackers. He called a special news conference to point out that the Clintons were the original promoters of the North American Free Trade Agreement – a treaty with Mexico and Canada widely blamed by struggling working-class Democrats for chasing jobs and companies out of the United States.
He put out an advert of his own to suggest that what he may lack in experience, Senator Clinton lacks in judgement – starting with her vote to authorise the Iraq war. He did his best to portray the Rezko scandal as old news and the trial as something that had little or nothing to do with him.
At the very least, though, Mr Obama lost control of both his own campaign message and the storyline being peddled on the television news and the cable chat shows in the all-important 24 hours leading up to the vote. Final tracking polls in both Ohio and Texas, the two key battlegrounds, suggested movement away from him. Despite multiple caveats about the reliability of polls in this see-saw of a primary campaign, he is still the favourite to win Texas – albeit by a small margin – but could lose Ohio by as much as 10 points.
In the two smaller contests also taking place today, Mrs Clinton is expected to win Rhode Island, while Mr Obama was on course to take Vermont.
Mrs Clinton's own husband, former president Bill Clinton, has acknowledged she needs to win both Ohio and Texas to snag the Democratic presidential nomination. Whatever her own feelings, she is likely to come under relentless pressure from her party to pull out if she loses one or both.
There is, however, a possible grey area somewhere between victory and defeat. If she loses Texas only by a tiny margin, or if – as is distinctly possible under the Lone Star State's arcane rules – she wins the popular vote but loses the delegate count, she may still try to make the case that the tide has turned and she has reason to keep campaigning for the Pennsylvania primary on April 22.
Complicating matters further was the weather. Forecasters predicted a withering ice-storm across much of northern Ohio, which could not only keep some voters away but could also knock out power at polling stations. In Texas, the area around Dallas in the north of the state was under a highly unusual snow alert, and the rest of the state was shivering in cold temperatures and bitter high winds.
None of that seemed to deter Senator Clinton at her final rally in Austin. Before she spoke, she sent a cheerleader out to warm up the crowd and teach them chants in preparation for tomorrow night's caucuses which will follow on directly from the close of the primary polls under Texas's peculiar hybrid system. "When I say 'Hillary', you say 'Texas'," the cheerleader yelled. "When I say 'Madam', you say 'President'!"
Mrs Clinton engaged in some cheerleading of her own by the end of her speech. "I'm ready if you are willing," she said. "Let's go out and make history tomorrow."