WASHINGTON (AP) — In a struggle steeped in election-year politics, supporters of the proposed Keystone XL pipeline are seeking a swift Senate vote on legislation to approve construction of the project that environmentalists oppose strongly and the Obama administration has delayed indefinitely.

Pipeline advocates in the Senate, who include several Democrats on the ballot next fall as well as Republicans, hold a clear majority. They also may command more than the 60 votes needed to overcome blocking tactics by opponents, but they appear to be short of the two-thirds majority that would be needed to override any veto by President Barack Obama.