Democrat Barack Obama pulled even with Hillary Clinton in Iowa, with John Edwards close behind, in a tightening three-way race one day before the first presidential nominating contest, according to a Reuters/C-SPAN/Zogby poll released on Wednesday. Obama gained two points overnight and Clinton lost two points to deadlock at 28 percent among Democrats in Iowa, with Edwards in a statistical dead heat behind them at 26 percent. No other Democrat registered in double digits. The Republican race in Iowa also tightened, with former Arkansas Gov. Mike Huckabee's lead over former Massachusetts Gov. Mitt Romney sliced to two points, 28 percent to 26 percent. Arizona Sen. John McCain and former Tennessee Sen. Fred Thompson were tied for third at 12 percent. "Both races are getting tighter as the caucuses get closer," pollster John Zogby said. The rolling poll of 933 likely Democratic caucus-goers and 907 likely Republican caucus-goers was taken Saturday through Tuesday and has a margin of error of 3.3 percentage points for each party. Obama, Clinton, and Edwards have battled for the top Democratic spot for months in Iowa, which on Thursday kicks off the state-by-state battle to choose Republican and Democratic candidates for the November presidential election. Obama, an Illinois senator, made small gains among independents and solidified his strength among younger voters. Clinton, a New York senator and former first lady, maintained her strong lead among older voters. Edwards, a former North Carolina senator, remained the top second choice of Democrats. A candidate must have 15 percent support in each precinct to be viable or their supporters can switch to another candidate.