HARTFORD, Conn. -- Sen. Hillary Clinton, who once had a comfortable lead among Connecticut Democrats, sought to fight off a late surge from Sen. Barack Obama as voters went to the polls Tuesday for a historic presidential primary.

Obama, a first-term senator from Illinois, is vying to become the first black candidate to win the nomination of a major U.S. political party; Clinton is hoping to become the first woman to do so.

Clinton, from neighboring New York, once held a commanding lead in polls in Connecticut, but has seen her advantage slip away as the once-crowded Democratic field narrowed to two choices.

They were competing for 48 delegates to the Democratic national convention, a tiny fraction of the 2,025 needed to clinch the party's nomination.

Clinton campaigned twice in Connecticut during the final days of the campaign, including a visit Monday to Yale University, where she attended law school. Later Monday, Obama drew 15,000 to a rally at the XL Center in Hartford.

State officials predicted record turnout that could approach 50 percent. The previous record was 43.3 percent turnout for the 2006 Democratic Senate primary between Sen. Joe Lieberman and challenger Ned Lamont.

"It's a close call," said psychology professor Tony Lemieux, 32, who voted for Obama on Tuesday morning in Milford. "My wife voted for Hillary. We're splitting the delegates, at least in our house."

The split was reflected at the highest levels of Connecticut government. Democratic U.S. Reps. Rosa DeLauro, John Larson and Chris Murphy backed Obama, while Attorney General Richard Blumenthal and Comptroller Nancy Wyman stumped for Clinton.

Sen. Christopher Dodd, who dropped out of the campaign after a poor showing in the Iowa caucus, did not endorse a candidate.

Former Congressman Sam Gejdenson, a Dodd supporter who voted in Bozrah on Tuesday, declined to say whether he picked Obama or Clinton but predicted they would split the state's delegates.

"I think they're both terrific, they're both very capable, they both, I think, have very solid ideas for the country," he said. "It's a very hard decision."