I know nothing about Bob Iger, but given what's happened these past few years, denial from the person and their family that they'll run for office is the first sign that they'll run for office.
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.