Don’t be silly. Of course the GOP can defend Trump. They can repeat into every mic in DC that there is zero evidence that Trump has committed a crime, and thus zero basis for impeachment. Then they can run through the impressively long, bipartisan list of people who are on record saying there is zero evidence of collusion between Trump and Russia. They can repeat these two facts until A, they sink in, and B, the ground is cut out from under the MSM/Democrats.
The GOP is trying to wear down Trump so he won’t run for reelection. LBJ is the correct historical parallel. Not Nixon. That’s what much of the backstabbing is about, IMO.
1. There is no need to even mention the word "impeachment" when you're dealing with a fabricated scandal like this.
2. There's no need for any Republican to do this when you already have people like Diane Feinstein, former FBI Director James Comey, and interim FBI Director Andrew McCabe on the record saying exactly what you've said here.