Clinton holds lead as Romney slips in Iowa

By John Whitesides, Political Correspondent

DES MOINES, Iowa (Reuters) - Democrat Hillary Clinton and Republican Mike Huckabee hold narrow leads on their top rivals two days before the state opens the presidential nominating race, according to a Reuters/C-SPAN/Zogby poll released on Tuesday.

Clinton, a New York senator, maintained a stable four-point edge over Illinois Sen. Barack Obama, 30 percent to 26 percent, in the Democratic race. Former North Carolina Sen. John Edwards was in third at 25 percent, down one point overnight.

Huckabee, a former Arkansas governor, widened his lead over Romney among Republicans to 29 percent to 25 percent. Romney, a former Massachusetts governor who has been on the attack against Huckabee, slipped two points overnight.

Arizona Sen. John McCain remained a distant third in Iowa's Republican race at 12 percent, with former Tennessee Sen. Fred Thompson gaining two points to climb to fourth at 10 percent.

The poll of 925 likely Democratic caucus-goers and 928 likely Republican caucus-goers was taken Friday through Monday and has a margin of error of 3.3 percentage points for each party.

Iowa is the first test in the state-by-state fight to choose candidates for the November presidential election, and about 7 percent of Democrats and 6 percent of Republicans remain undecided after months of heavy campaigning

Clinton, Obama and Edwards have been battling for the top Democratic spot for months. Clinton, a former first lady who would be the first woman president, leads among women and older voters who are most likely to turn out for a caucus.

But Edwards remains the top second choice of Democrats, a potentially significant factor given the requirement a candidate have 15 percent support in each precinct to be viable or their supporters can switch to another candidate.