DES MOINES, Iowa (AP) – Barack Obama, Hillary Rodham Clinton and John Edwards closed out a long, grueling Iowa caucus campaign Wednesday night with statewide television appeals, each seeking an early triumph in the race for the 2008 Democratic presidential nomination. Leading Republicans exchanged routine unpleasantries on a final day of campaigning.

“You just don’t know what is going to happen,” confessed Mitt Romney, unwilling to forecast success over Republican rival Mike Huckabee in Thursday’s first contest of the race for the White House.

“This country is ready for a leader who will bring us together,” Obama said in a two-minute commercial televised at the dinner hour. A first-term Illinois senator seeking to become the nation’s first black president, he added, “That’s the only way we’re going to win this election. And that’s how we’ll actually fix health care, make college affordable, become energy independent and end this war.”

Clinton, seeking to become America’s first female president, reached out with a campaign-closing commercial broadcast of her own. “If you stand with me for one night, I will stand up for you every day as your president,” she said. “I’ll work my heart out to bring the country we love the new beginning it needs and I will be ready to start on Day One.”

Edwards’ campaign selected Doug Bishop, a laid-off Maytag worker, to deliver a televised pitch for the former North Carolina senator.

“I want a guy that’s going to sit down and look a 7-year-old kid in the eye and tell him, ‘I’m going to fight for your dad’s job,'” Bishop said as he introduces Edwards to an Iowa crowd. “That’s what I want. I’m going to do my best to make sure that my children aren’t the first generation of Americans that I can’t look them in the eye and say, ‘You’re going to have a better life than I had.'”

Increasingly, the candidates looked beyond Iowa to the states that quickly follow. Republican Sen. John McCain spent most of the day in New Hampshire, which holds a primary on Jan. 8, and his campaign ordered television advertising in Michigan, with a primary one week later.

But first there was Iowa, snow piled high and frozen – and an electorate warmed by the attention of Republican and Democratic hopefuls in the most wide-open presidential race in a half-century or more.

Late pre-caucus polls generally pointed toward a close three-way finish among Democrats and an unpredictable two-man struggle for the Republicans. A quarter of likely caucus-goers reported they either had not made up their minds or could still change them. That wasn’t a surprise in Iowa, where 21 percent of participants in the 2004 caucuses said they had made up their minds in the final three days .

That only added to the urgency of the campaigns, which stood ready with snow shovels and baby sitters – to make sure supporters were able to leave home for the caucuses – and delivered reminders to voters via Facebook and phone. Romney said his campaign made 12,000 calls on Sunday alone.

Unsurprisingly, there were reports of campaign dirty tricks – anonymous phone calls to Romney supporters directing them to incorrect caucus locations, and a recorded message disparaging former Sen. Fred Thompson of Tennessee, who hoped for a third-place finish to rescue his faltering candidacy.

There were predictions of a heavy Democratic turnout from election officials in scattered locations, who also reported independents switching their registration to Democratic so they could vote. “From what I can ascertain from the calls that we’re getting, it looks like the Democratic caucuses are just going to be flooded,” said Richard Bauer, elections supervisor in Scott County along the state’s eastern edge.

Obama, in particular, has bet his campaign on the support of first-time caucus-goers, independents as well as Democrats who could be attracted to his message of political change. A victory in Iowa would validate the strategy, and presumably give him a boost in New Hampshire, where independents can vote in either primary.

At the first of five stops on Wednesday, he brushed aside claims that he might be too inexperienced for the job. “The real gamble would be to have us do the same old things with the same old folks over and over and again,” he told a crowd of several hundred in Davenport, across the Mississippi river from his home state of Illinois.

Clinton, who raced through five appearances, started out by bringing bagels, fruit and coffee to her volunteers in Des Moines. “I know if you’re here from Iowa to help me, this is like, nothing,” she said, referring to temperatures in the single digits. “But we have staff and volunteers who’ve come from exotic climes like California and they’re freezing.”

Edwards, the party’s 2004 vice presidential nominee, willed himself through a final 36-hour campaign whirlwind. He raced through 12 stops during the day, at each one summoning Iowans to battle special interests in Washington by launching him on his way to the White House.

He criticized the Bush administration for granting no-bid contracts to Halliburton and complained about tax breaks for the wealthy. “When will it stop? It will stop when we stop it,” he told a group in the Ivy Bake Shoppe in Fort Madison.