I really disagree with that analysis. During Watergate, 2/3 of the Republican members of the Judiciary Committee voted against all impeachment charges. And that’s after there was an actual audio recording of the President committing the crimes he was charged with. Direct evidence like that is very rare, even in normal criminal cases–usually convictions hinge upon a pile-up of circumstantial evidence that can’t be explained away by any other plausible scenario (i.e. “beyond reasonable doubt”). That’s much more likely to be the case here.
So if the case against Trump never gets as bulletproof as the case against Nixon, I’d say well over 2/3 of the Republican members of the relevant committees will avoid taking any action at all. Which is more than enough to ensure nothing happens. And Republicans won’t see any blowback regardless of how big the scandal becomes. As long as Trump’s approval stays above ~32%, they keep the Senate–with no real risk of losing it until 2022. The House is theirs until 2022 even if voters overwhelmingly prefer Democrats–and it’ll likely remain theirs after 2022 if they keep control of the redistricting process. What other changes may happen to our election system before 2022 is also worth considering.
If the scandals keep going at their current rate (major scandal every 12 hours or so, no actual video footage of Trump eating the puppy, just twelve witnesses), I think we’re looking at a second Trump term. That’s not doomed.
I think there are some additional factors to take into consideration here. One of them is that Trump has already made quite a few enemies in Congress, and he’s proving to be an embarrassment in terms of policy. Nixon was at least a savvy politician. There is also the matter of the crime. The Russia collusion has the potential to be much bigger than Watergate, if any hard evidence surfaces. Of course, there has been an erosion of values in Congress leading them to look the other way even when faced with wrongdoing, so perhaps these factors cancel out. But I don’t think that he is in a better position than Nixon at this point in his presidency.
Sure, there’s never a 100% perfect analog. That’s the perennial problem with using historical precedents to predict current events. But I think that it’s pretty clear (to me, at least) that if Republicans ran both houses of Congress, Nixon would never have been forced to resign, in spite of direct evidence of criminal wrongdoing. That doesn’t bode well.