Democratic presidential front-runner Howard Dean holds a narrow two-point lead over Missouri Rep. Richard Gephardt in Iowa barely one week before the state's caucuses, according to a Reuters/MSNBC/Zogby poll released on Sunday.
The former Vermont governor led Gephardt 25-23 percent in the three-day tracking poll, with Massachusetts Sen. John Kerry in third place at 14 percent and North Carolina Sen. John Edwards moving up to a close fourth at 13 percent.
"It's very, very tight," pollster John Zogby said. "It's a close race and it probably will go right to the end."
The poll of 500 likely caucus-goers was taken Thursday through Saturday and has a margin of error of 4.5 percent. The rolling poll will continue each day through the Jan. 19 caucuses.
The Iowa caucuses are the first meaningful prize in the Democratic race for the right to challenge President Bush in November, and Dean and Gephardt have been locked in a tight duel at the top in Iowa for months.
With eight days to go until the caucuses, 14 percent of likely participants are still undecided, the poll found.
Dean led among the very liberal, independents, young voters, the college educated and singles, while Gephardt led among union households, those with less than a college education and lower income voters.
The survey also found growth for Edwards, who gained strength during the course of the three days and earned the endorsement of the state's largest newspaper, the Des Moines Register, on Sunday.
"Edwards has picked up a lot of steam each night," Zogby said.
Connecticut Sen. Joseph Lieberman and retired Gen. Wesley Clark, who are not competing in Iowa, were each at 3 percent in the poll, with Ohio Rep. Dennis Kucinich at 2 percent.
Civil rights activist Al Sharpton and former Illinois Sen. Carol Moseley Braun were at 1 percent each.
Dean, the one-time longshot who has roared to the front of the Democratic field nationally on the basis of his outspoken criticism of Bush, the Iraq war and Democratic Party leaders, had a roller-coaster three days during the polling.
The survey began on Thursday as four-year-old tapes surfaced showing Dean criticizing the Iowa caucuses as dominated by special interests, and continued on Friday when Iowa's most influential Democrat, Sen. Tom Harkin, endorsed Dean.
Zogby said Dean had a bad Thursday night as news spread in Iowa of his critical comments about the caucuses, made on a Canadian public affairs program, but recovered on Friday with the endorsement from Harkin.
"It could not have come at a better time for him," Zogby said.
Gephardt's backers were the least likely to change their mind, with 31 percent calling their support "very strong." Twenty-six percent of Dean's support was "very strong," with Edwards at 18 percent and Kerry 14 percent.
Polling in Iowa is complicated by the unique nature of the caucus system, which requires participants to leave their homes on what is typically a bitter cold night and gather with neighbors for hours before publicly declaring their support for a candidate.
The ability to identify and turn out supporters is critical to each of the campaigns. The Zogby poll only included respondents who said they were likely to attend the caucuses.