Reply #5: Tell him he needs to back off. You disagree about politics, and him becoming louder and more

[Mayberry Machiavelli]

strident is not the way to go, it will do nothing but end any friendship that exists.

That if he respects your sense of limits he should stop spamming your email with right wing baloney.

Then if he doesn't respect your request and back off, friendship over.

I've had to do this, and the people involved HAVE backed off.