They could certainly get enough votes to impeach simply along party lines. To remove him, however, is something totally different. Often people conflate the two. He is not going to be removed. That would require like 20+ Republican and all independents to vote to remove, plus all Democrats. So the question is if impeaching, but not removing him, would affect the Democrats in 2020, or if that would just be another let-down that gets spun as a moral victory but doesn't reach the goal in everyone's minds currently (which is removal rather than just impeachment).
As an aside, people who hated Clinton (and Obama) looked really silly when their wishful fantasies had them believing that Clinton being arrested was just around the corner! Every turn, there was reassurance of how she was about to be brought down because of ____ (and Obama, too). Yes, I get it, "but this is different!" Ultimately, he won't be removed. The goal-post will shift, another "constitutional crisis" will arise and that one is really going to take him down! Just like Clinton. If the right could have been more self-reflective about their wishful fantasies being just that, they could have saved themselves a lot of embarrassment. When the tables turn, the left is as self-reflective as those they despise. Yeah, "but it's different!!" Bottom line is that he won't be removed from office, and those arguing that he will be will have some spin on the corruption of why he wasn't (when it never comes to fruition).