The vote is being kept open as the Senate awaits John McCain’s arrival. He flew into DC from Arizona a short time ago. If the vote goes as expected, he’ll be the 50th vote, creating a tie that Vice President Mike Pence will break.
The final gavel has not fallen yet, but the only two GOP no votes right now are Lisa Murkowski (AK) and Susan Collins (ME). The only other GOP senator who hasn’t voted yet is Ron Johnson (WI). It’s not clear why Johnson hasn’t voted yet. He and Majority Leader Mitch McConnell are currently talking on the Senate floor.
The scene of a dramatic return by McCain seems by design, perhaps to cloak the bizarre process in some seriousness.
Update: McCain cast 49th yes vote, and Johnson cast the 50th. No final gavel yet. But should be soon.