But one veteran Republican observer who requested anonymity notes that Trump’s slide in the polls has opened up a large gap in key Senate races between the percentage of the vote that Trump is getting and the percentage that the Republican Senate nominee is getting.

“As we approach the election, that gap could close – and not to the benefit of Republican Senate candidates,” worried the Republican who cited turnout, state voting patterns and Trump’s weakness as problems for GOP Senate nominees in tight races.

Before the Trump tape issue emerged, there was no indication that a national partisan wave had developed. That’s important, because in a partisan wave Senate seats often fall in one direction. However, the lack of a wave in no way guarantees the two parties will “split” toss-up races, and Trump’s candidacy is so damaged that experienced Republican observers are extremely nervous.

But while the Trump campaign’s implosion obviously ratchets up the risk for the GOP, it may not be fatal. Trump’s supporters are intensely loyal and energized, and Clinton’s personal ratings remain poor. Her weakness gives Republican candidates an opportunity to attract voters who dislike both presidential nominees by returning to their “don’t give Hillary Clinton a blank check” message.