People who are quick witted, how?

I just lost a political argument with a friend because I couldn’t think of responses on the fly. It’s like every fact I knew suddenly disappeared from my head. However, the literally 5 minutes after we stopped arguing, I come up with these genius comebacks but it was too late. So, how do you quick witted people come up with responses so fast without blanking?

EDIT: The politics argument was in a friendly way to discuss our opinions, nothing serious. We’re still friends lol