For decades, albeit post Nixon's time, the GOP was further limited by a rotten consent decree which prohibited them from even trying to fight back. That only ended when the octogenarian lefty judge maintaining it finally died. Trump is not only the first Republican to try to fight back, he's the first in decades allowed to fight back.
Perhaps he could fight better, but he's figuring it out as he goes and and an awful lot of reasonable attempts have been summarily blocked by embedded forces of the left.
The fact is Nixon lost under dubious circumstances, conceded, then came back and won, that is a fact all the other rationalizations are just that