Why does that have anything to do with race, though? When Gingrich started, the hyper-adversarial approach was new; he had only a couple years at it before Clinton was up for re-election. There wasn't time to establish that as a reasonable strategy instead of destructively petulant childishness, which is what it would have been viewed as before. (Wanting to win wasn't new; having no tact about stating it and acting on it was new.)

Obama was the next time we got to measure the hyperpartisanship directed against a Democratic president. McConnell's stated goal was an abject failure--Obama beat Romney handily. But Mitch's statement was exactly in-line with the win-at-all-costs mentality that was replacing the stiff-competition-then-get-things-done-in-back-rooms mentality that it was replacing, and also exactly in line with the "sky is falling America is doomed if they win" rhetoric that they were bringing out against Democrats every time.

Of course, that doesn't play well when you have a new President elected with a handy majority, so McConnell started out singing a different tune: https://www.cnn.com/2009/POLITICS/04/27/congress.100.days/index.html

And this time round, the Republicans--now that they have a bit of power--are taking an even meaner tactic, saying their top tactic is to investigate Biden's family. https://www.bbc.com/news/world-us-canada-63665351

It's disturbing and pathetic, but it follows the same trend. It's not like the Republicans have scaled anything back now that an old white guy is in the Oval Office again, because the old white guy is a Democrat. That is the identity marker that matters ten times more than everything else put together.