Everyone already knows what goes through McCain's mind:
"Soon, I shall rule this land! BWAHAHAHAHAHAHAHAAAAAH!!!!"
There is a powerful win-win scenario for the President. If the bill is delayed into the new Congress, because the Dems think they can take the House and open the border completely, then the base can galvanize and turn out in record numbers to be DAMN SURE the GOP holds the House at least and maybe Senate too.
This would preclude impeachment.
That's a viable strategy. Just delay it to the next Congress. Then we have no choice but to make sure the GOP holds the House. Everyone will show up to vote that way.
And as for having no sympathy for the Senate RINOs, we won't have anything to say about that because of the large number of GOP senators running, only 3 are RINOs. Staying away from the Senate would hurt only conservative Senators.