At the pub no less.
Once you ascertain the other parson is sane, I put it simply.

You are GOP, not GQP. Once they agree to that simple point you can get along.
Chances are the true Republican hates what has happened. My friend does.
Now we can get to what we agree on instead of GQP bs.

If you don't separate the two, moving on will be almost impossible.
I found his response to this agreeable and we can discuss many issues.

GOP or DEM. We are all Americans first. GQP? Hell no.

Thoughts?