I happened across a set of polling results today that I think contains kind of a "smoking gun" indication that Trump is hurting the Republican Party. It's polling of a large sample of 2018 mid term elections voters reported at
https://www.wsj.com/graphics/election-2 ... cast-poll/.
One set of results is for how people voted depending on whether Trump was a factor in their vote. Among those who said Trump was NOT a factor in their vote, Republicans actually had a 55% to 40% edge. But among those who said Trump WAS a factor in their vote, Republicans got beaten by 58% to 41%.
That dichotomy was a problem for Republicans because 64% said Trump was a factor vs. 35% who said he was not. He was clearly a net negative for the Republicans.
BTW I don't think there's clear evidence he was a net positive for them in the Senate races either. He endorsed 21 Senatorial candidates. 11 won and 10 lost. He appeared on stage at rallies with 15 of them. 7 of those won and 8 of them lost. Those numbers are from the article at
https://www.npr.org/2018/11/08/66530925 ... dates-lost except the Mississippi Senate race is now known to be a win. All that happened in the context of a situation in which everyone knew from the start that the 2018 election Senate playing field was tilted significantly in the Republicans' favor.