Well, consider: You're a Senate Republican. Obama nominates a guy who is certainly no Scalia but legitimately isn't the worst. You can hold out and hope that a Republican gets elected, but there's a good chance that'll be Donald Trump, and what kind of a judge is that weirdo going to nominate? You hate that guy and think he's a blemish to the name of the Republican party. Also, there's still a real risk Hilary/Sanders will win instead. AND you can expect to face more than half the media harassing you over any delay. In fact, the harassment has already begun today, Feb 13.

So a real compromise candidate might be possible. It'd likely depend on Obama and the senate Democrats as well, though.