I think part of the problem is also that McConnell and the Senate Republicans have no respect for Reid and the Senate Democrats. They know the Democrats are “reasonable” and “respectful of Senate tradition” (ie, pussies). They know that, if the situation were reversed, no Democrat would pull this stunt. They know that, if they do pull this stunt, and they themselves face a similar situation in the future [lame duck GOP President in his final year, a Democrat-majority Senate], they’ll face no retaliation (ie, the Democrats would be “reasonable” and actually vote on a SCOTUS nominee).
These Senators can’t be impeached for this. Their electorate will reward them for this. There’s just no downside to this betrayal of the constitution.
Unless Reid actually had balls and made it clear to them that this would be War. They might get away with it, but it will be War from here on out. And, should the Democrats ever get power again, they won’t forget the stunt, they’ll do everything in their power, including abolishing the filibuster, including using the “nuclear option” in approving nominees. Reid has some power. He just never uses it. Democrats should, at long last, stop being “reasonable.”