I can see the conversation before the dummie gets there:
"Everybody, listen up. We all know what a loon <dummie name> is, but he is our loon so in the interest of having a peaceful dinner, nobody start any conversation that can be even remotely considered political. Remember what happened last time!!! We like to never got <dummie name> to shut the hell up.
I'm betting that conversation goes on with every dummie family.