It's not getting passed in Congress specifically because Trump told Thune that he would publicly go after any Republicans who supported it.
I think I read reporting where he even asked Thune for names of any of the Senators who supported the idea behind closed doors, but I could be mistaken on the part, so definitely don't take my word on that specific detail.
Right... Except impeachment was never on the cards for this congress, but a bill to resume funding the rest of DHS was, which is what this article is about...