How do you deal with someone who cannot be reasoned with?

I do not.

If the car is blocking the driveway call the local police, otherwise it’s a public street

Hahah I like your grouping. I’d egg his car from inside the house then stand flat footed and lie to the police when they showed up.

Stop talking about me like I can’t hear you.

It depends on my mood. Sometimes I walk away and other times I lose it a little bit.

It is impossible! People like this are so flippin’ narcissistic in my opinion they don’t really listen to other people, they don’t give a shit about anything except what is important to them. I find them to be needy, unhappy, selfish people unable to put themselves in the other persons shoes. If you have the time to psychoanalyze them and figure out where their pain comes from and what they need to be able to listen to others, and if their request is reasonable you might be able to deal with them, but I can’t see that happening with the Taliban or an asshole who parks in front of your driveway over and over again. The only time it is sometimes worth your time is if they are family members who you love and need to figure out a way to get along better, assuming they are willing to work on the problem also.

Don’t waste your breath or time with them. Just call the police and have them handle it. That’s their job.

If someone’s blocking your driveway, call the police and have the car towed. That usually takes care of it much better than getting into it with them.

I try to reason with her. When that doesn’t work, I find that my desire to keep the company of others wanes, and I end up at home on New Year’s Eve watching cartoons.

I put them in a big slingshot and hurl them into the sun.

I live with someone like that. That’s why I am in therapy.

I marry them.

As far as extremist groups in foreign countries I have no sensible solution.

There are legal remedies for dealing with unreasonable people who cause you damages or harm. If that does not apply, be an adult and ignore them!

People who can’t be reasoned with who are a threat, need to be subdued.
Once subdued (assuming they survived it) they can either be reasoned with or subdued further.

Just leave them alone.