DENVER (AP) -- Battleground Colorado is edging slightly closer to Republican Mitt Romney, but President Barack Obama is still leading after last week's presidential debate at the University of Denver.

A poll commissioned by the school showed Obama leading Romney among likely voters by 4 points, 47 percent to 43 percent. The poll had a 4-point margin of error.

The DU poll also 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 recognizing same-sex couples. Seventy-three percent supported legal recognition of same-sex relationships, either marriage or civil unions.

The telephone survey included 604 likely voters. It was conducted Oct. 4-5 by Selzer & Co. of Des Moines, Iowa.