DENVER - Boosted by a strong performance in the first presidential debate in Denver, Republican Mitt Romney edged closer to President Barack Obama in a Colorado poll released Sunday.Obama clung to the lead in a poll commissioned by the University of Denver, which hosted the debate. The poll showed Obama leading Romney among likely voters, 47 percent to 43 percent. The poll had a 4-point margin of error.An earlier poll, released Sept. 20, showed a slightly wider lead for the president, 50 percent to 45 percent among likely voters. That poll had a margin of error of plus or minus 3 points and was conducted by NBC News/Wall Street Journal/Marist.In the DU poll, more than 80 percent of the likely voters said they watched the first debate, and they overwhelmingly thought Romney did better. Sixty-eight percent said Romney did better than Obama. Two more debates are planned.The poll showed a tossup for the marijuana legalization question. Fifty percent planned to vote for legalizing pot, 40 percent planned to vote against it, and 10 percent weren't sure. Coloradans were more united on the question of same-sex couples. Seventy-three percent supported legal recognition of same-sex relationships, either marriage or civil unions. Earlier this year, Republicans in the state Legislature blocked a Democratic-sponsored civil unions measure. The DU telephone survey included 604 likely voters. It was conducted Oct. 4-5 by Selzer & Co. of Des Moines, Iowa.On immigration, Coloradans favored allowing illegal immigrants to stay, keep their jobs and eventually apply for legal status. Sixty-three percent said they preferred that position on immigration, with 31 percent saying illegal immigrants should be deported to their home country. Asked about illegal immigrants who came here as children, the margin widened slightly, with 68 percent favoring allowing those illegal immigrants to stay and 24 percent opposing the new policy allowing illegal immigrants brought as children to obtain work permits and not face deportation.Coloradans were more divided on the new health care law. Thirty-eight percent said the law should be repealed. Thirty-four percent said it contains good provisions but may need adjustments. And 16 percent said the law is good and should remain as is.Asked to give their impressions about politicians from both parties, Coloradans gave higher marks to Democratic Gov. John Hickenlooper than to either presidential candidate. Sixty-eight percent said they had "very favorable" or "mostly favorable" feelings about the governor.