Senate Majority Leader Harry ReidHarry ReidConservative Senate candidate calls on GOP to end filibuster Ex-Reid aide: McConnell's 'original sin' was casting ObamaCare as 'partisan, socialist takeover' GOP faces growing demographic nightmare in West MORE (D-Nev.) has called for senators to be in their seats for the final vote on immigration reform, which could come as soon as Thursday.

“Everyone knows we’re poised to pass a historic immigration bill,” Reid said on the Senate floor. “This is not a vote where people should be straggling in.”

The Senate rarely requires members to be seated and answer the clerk when their name is called. The last seated vote was on the United Nations Convention on the Rights of Persons with Disabilities nearly a year ago. That measure ultimately failed.

“I’m going to ask that senators be seated,” Reid said. “This vote is important enough, no matter how you feel about the legislation, that we do that.”

Reid also urged those opposing the immigration reform bill to accept the “inevitable” and allow a vote Thursday evening rather than waiting until Friday.

The Senate will vote at some point on Thursday to end debate on the immigration reform bill, S. 744. Unless a deal is reached to hold a vote on final passage sooner, the vote will be Friday afternoon.

The sweeping legislation from the Senate's Gang of Eight is expected to pass with bipartisan support, and could come close to the 70-vote majority that supporters have sought.