Clinton leads in Iowa but Edwards gains

By John Whitesides, Political Correspondent

DES MOINES, Iowa (Reuters) - Democrat Hillary Clinton holds a slim lead in Iowa over Barack Obama and a rising John Edwards, who are tied for second place three days before the state opens the presidential nominating race, according to a Reuters/C-SPAN/Zogby poll released on Monday.

In the tight Republican contest in Iowa, Mike Huckabee narrowly leads Mitt Romney, who slipped by one point to trail 29 percent to 27 percent. John McCain gained two points but remained a distant third at 13 percent.

About 6 percent of likely caucus-goers in each party remain undecided of their choice in Thursday's contest, the first big test in the state-by-state battle to choose Republican and Democratic candidates in November's presidential election.

"It's about as close as you can get at the top in both races," pollster John Zogby said. "But it's still very uncertain."

The poll of 899 likely Democratic caucus-goers and 902 likely Republican caucus-goers was taken Thursday through Saturday and has a margin of error of 3.3 percentage points for each party.

Most of the top candidates in both parties have been crisscrossing Iowa for days in a late hunt for support that could give them an edge and momentum for later contests.

The poll showed Clinton, a New York senator and former first lady, leading Edwards and Illinois Sen. Obama by four points, 30 percent to 26 percent. Edwards, a former North Carolina senator, gained two points overnight to pull even with Obama.

Delaware Sen. Joseph Biden and New Mexico Gov. Bill Richardson were at 5 percent. Connecticut Sen. Chris Dodd and Ohio Rep. Dennis Kucinich were at 1 percent.