They're just sitting on the vote, have been for more than 50 minutes now. It's 1 AM in DC land, and they are still on the floor. 538's guess is that that means that the leadership knows they aren't at 50 and are trying to cajole recalcitrant senators into it before they send it up. Twitter is going mad trying to calculate the meaning of McCain's body language, and the betting markets fluctuated from 60-70% or so down to 45%. I don't think anyone knows how this will go down.
EDIT: It seems like McCain is going to vote no? Someone for NY Times claiming two people with knowledge of McCain's thinking says he's a no.
EDIT2: C-SPAN doesn't know what's going on either. Pence is trying to work McCain.
EDIT3: Vote is finally starting?
EDIT4: McCain votes no. Murkowski votes no. The "Ayes" sound very soft, the "No"s are loud.
FINAL-EDIT: Well unless this is a MASTERPLAN that I am unable to understand, this looks like a nasty defeat for Republican Congress, and for Mr. Trump, courtesy of a Mr. John McCain. Whoda thunk it.
Actual final edit: It's over. Officially. Skinny Repeal dies by exactly one vote. McConnell takes the floor, is basically saying "Hey, we worked hard, and we tried." Now amendment lightning round begins, where people throw amendments at the wall.