There is a difference between disagreeing about the proper way to tax an economy, or the proper way to regulate a market on the one side, and Trump on the other.

I think big disagreements about religion or politics can make deep friendship impossible. It is one thing to put some issues under the rug and agree to disagree. But some things are fundamental and have to do with your level of decency and moral compass, or your ability to discern the truth.

You call your friend a radical. But your only example is him as a college student once making a comment about a bomb, which was a long long time ago and might have been a tasteless joke, and in your comment there is no link between that and politics.

My initial comment was a bit blunt, but it was to make a point. Maybe your friend does have views I think would make him fundamentally incapable of being my friend. But if a political disagrement does occor, as a result of this election, it just makes something visible that was always there. And both of you may be reactionary in your views, becoming either more outspoken or extreme.

But if you disagree that strongly and both of you don't feel like your disagreements and discussions have value, but instead both of you become frustrated by it, that is not a good sign. I do not know what the exact nature of this friendship is, but it seems like a deep emotional bond is being severed, which can be understandable.

You can either try to try to come closer together in political views through debate, or you can try to give your friendship some different nature. Like someone you visit sports events of go fishing with, but with whom you would not discuss for example your marriage.