Want to bet? It is quite possible.
All the Dems need is 34 votes for it if the Dems sneak an unexpected vote in with a bare quorum in attendence some unexpected time when the GOP isn't paying attention - which is most of the time. All they need is a quorum (50+1) on the floor and a quick vote (even a voice vote might do). They easily have enough votes for that. They could secretly set an ambush vote up ahead of time to catch the solmnolent GOP unawares.
Do you put it past them? It sounds just like how they would do it. Do you think McConnell or anybody else on our side is paying attention? All of a sudden, it will be done and over - and legal.
Not so. To ratify a treaty, the Constitution requires 2/3 approval by the full Senate -- i.e., 67 votes.
I wouldn’t want that bet. The unfortunate reality is, however, 2/3 of Senators present. That said, I doubt it will happen and hope it won’t because I’m too old and tired to get involved in any more wars. Trite current tagline still holds.