— WASHINGTON (AP)   Senate Democrats set aside their effort Wednesday to win support from conservative Sen. Tom Coburn for requiring federal background checks for nearly all gun purchases, at least temporarily hurting President Barack Obama’s chances for pushing one of his top priorities through Congress.

Democrats’ failure to resolve a final dispute with the Oklahoma Republican means they’ve lost a valuable ally, at least for now. Coburn has an A-rating from the National Rifle Association and could have prompted backing from other Republicans and from moderate Democrats from GOP-leaning states leery of alienating voters.

In addition, gun-curb supporters say the Senate will have to approve legislation with strong bipartisan support to boost their chances of success in the GOP-led House. Republican leaders there have said they won’t act until the Senate produces legislation.

Senate Democrats instead will seek backing from other Republicans for what they still hope will be a bipartisan drive to expand the current background check system, said an aide to Sen. Chuck Schumer, D-N.Y., who has been leading the Democratic effort.

The aide, who spoke only on condition of anonymity because the talks were private, said conversations with Coburn would continue. But it was clear that Democrats’ focus was shifting elsewhere.

Requiring nearly universal background checks is the foundation, and most popular part, of the proposals to curb firearms that Obama unveiled in January. That package came a month after the shooting massacre at an elementary school in Newtown, Conn., of 20 first-graders and six staffers.

Currently, the checks are required only for sales by the nation’s 55,000 federally licensed gun dealers, not for private sales between individuals, like those at gun shows or online. An Associated-Press-GfK poll in January found 84 percent favored requiring background checks at gun shows.

The talks between Coburn and Schumer foundered because Schumer was insisting that records be kept of private gun sales, perhaps by the seller, the manufacturer or others. Negotiations had lasted weeks and the two sides were stuck on the issue for some time, so Wednesday’s development was not a surprise.