Because as a very practical matter, TrumpII is as far as it can go. So Senators can be receptive to things that make them look good while still trying to either seek President Trump's favor, get re-elected, OR keep their distance from Trump and maybe have the Republican Senatorial Committee punish them.
If we keep the House and flip the Senate I think TrumpII is going to be Mr. Frog's Wild Ride for 2 years. The Democrats are going to use the migras this time to riot for them instead of the blacks. Burn their deportation encampments, etc. It ain't gonna turn out so well for the neomarxists this time -- why do you think we are pre-loading their cities with the worst of the worst?
Pass the candy and the popcorn.
Trump is and will always be the wild card. He looked around and saw that US politics seemed to be a game that anyone could play. (”O’bozo” is living proof of that) So he ran for President himself rather than become a pawn to men he couldn't respect. He succeeded in that twice and will again!