WRAPUP 1-U.S. candidates make final plea before Iowa vote

DAVENPORT, Iowa (Reuters) - White House hopefuls barnstormed across Iowa in a frenzied plea for support Wednesday, with polls showing deadlocked races in both parties the day before the state's contest kicking off the process of choosing U.S. presidential candidates.

Rolling through the frigid small towns of the rural Midwestern state or hopping between cities by plane, Democratic and Republican candidates asked supporters to turn out and searched for undecided voters they could persuade.

"I promise you this -- we will not just win the caucus, we will win the primary, we will win the general election and we will change this nation and change the world," Illinois Sen. Barack Obama told a rally in Davenport.

Iowa is the first test of the state-by-state battle to choose presidential candidates in November's election, and a Reuters/C-SPAN/Zogby poll Wednesday showed the races on both sides essentially deadlocked.

Hillary Clinton, a New York senator, and Illinois Sen. Barack Obama are tied among Democrats at 28 percent, with former North Carolina Sen. John Edwards close behind in a statistical dead heat at 26 percent.

Former Arkansas Gov. Mike Huckabee led former Massachusetts Gov. Mitt Romney by two points, well within the poll's margin of error.

The Democratic caucus begins at 6:30 p.m. CST ), with Republicans starting 30 minutes later. Results could begin to appear within an hour or two.

Clinton, Obama and Edwards all bought time on Iowa television to offer closing messages to voters Wednesday night.

STAND WITH ME

"If you stand with me for one night, I will stand up for you every day as your president," Clinton said in her two-minute message to air on Iowa stations.

Edwards, in the midst of a 36-hour marathon sprint around the state, campaigned through the night. He has been inching up in polls and drawn fire from both Clinton and Obama in recent days.

"Most of the other major candidates have been spending a lot of time talking about me," Edwards said on ABC's "Good Morning America."

"I think the reason for it is pretty straightforward. They can see this movement and explosion that's happening in my campaign right here and I think they're trying to blunt it," he said.

Republican Huckabee has been under fire for a news conference Monday where he announced he would not air an attack ad against Romney, then showed it to reporters.

The incident followed several days of attacks from Romney, who criticized Huckabee's record on immigration, taxes and crime while governor of Arkansas.

"I might have done it differently, but here's the real issue, the issue is we pulled ours. We didn't run a negative campaign, Mitt Romney did," Huckabee said.

"If we had stayed with it we would have exposed some things about his record that I think would probably have made a difference here in these last days."

The new Zogby poll showed Huckabee's standing slipping among his religious conservative supporters. But he is taking a break from Iowa Wednesday afternoon to head to California and appear on NBC's "Tonight" show with Jay Leno.

He will return immediately after the taping.

"We'll still be campaigning, in the meantime more people will see me in Iowa on Jay Leno tonight," he said. Leno's show is the top-rated late-night talk show on U.S. television.

Arizona Sen. John McCain, who has largely bypassed Iowa to focus on next Tuesday's primary contest in New Hampshire, is rising in polls in both states. He will return to Iowa Wednesday for events later in the day. (Additional reporting by Ellen Wulfhorst, Ed Stoddard, Joanne Kenen; writing by John Whitesides; Editing by David Storey) (For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at http://blogs.reuters.com/trail08/)