(Added on a few names)
George W. Bush: No. I don't think Trump will even try to get his endorsement. The bush name is bad enough as it is and Trump hates the Bushes even more than the average american.
Jeb Bush: No. Same reason as above.
George H.W. Bush (if still alive): No. Same reason as above.
Susan Collins: If she's governor of Maine by then, No. She would be firmly detached with Washington and endorsing Trump wouldn't make sense politically either given Maine's dem lean. If she's still a senator, maybe, though it might require some sort of reward, like a cabinet position.
Jeff Flake: No, mostly because Sinema will have his seat.
Lindsey Graham: Yes
John Kasich: No. He'll be primarying Trump, or endorsing whoever does.
John McCain (if still alive): No, unless Trump is extremely nice to him.
Lisa Murkowski: Yes
Mitt Romney: Yes if he's a senator, No otherwise.
Ben Sasse: LOL No.
Mark Kirk: No, mostly because he'll probably be irrelevant.
Bruce Rauner: No, because it makes sense politically for him to refuse.
Charlie Baker: LOL No.
Does Sasse survive his primary if he refuses to endorse?
