Chainsaw diplomacy. You say something that unequivocally you would not be able to flip on later. "Haha, but no way. I might be able to run Disney for 20 years,

Chainsaw diplomacy. You say something that unequivocally you would not be able to flip on later. "Haha, but no way. I might be able to run Disney for 20 years, but I could never run a country. I'd have to be an arrogant fool to think my business experience converts to governance experience, and I'd definitely screw it up. Besides, I would make an awful politician, I..." etc etc etc. Don't politely deny it, torpedo the idea.