The Democratic leader still faces skeptics in his ranks and hostility from some activists, but aides say he has enough commitments of support to be elected majority leader.
Senator Chuck Schumer, Democrat of New York, and his political team engaged in a $550 million push to put more Senate seats in play and increase their chances of regaining the majority.
Democrats are up in Michigan, Texas, Kansas, Maine and Ohio, have an edge in Alaska and are effectively tied with Republicans in Iowa, new New York Times/Siena polls found.