The things you listed were not defining moments. They were just things that happened. A defining moment can be quoted or viewed on film. Reagan’s “there you go again” is another one. George H.W. Bush looking at his watch was another. Al Gore stalking George W. Bush was yet another, as was Michael Dukakis’s tank ride. Nixon sweating, Ford saying eastern Europe wasn’t under soviet influence.
You're either not understanding my point or you're just too interested in arguing to get it. Your position is a result of EXACTLY what I'm talking about, because those indeed WERE defining moments...UNTIL THEY WEREN'T. That's exactly what all this "defining moment" silliness is. "Defining moments" as you again repeat them are mythology we decide MEAN something, when no one cared about Bush looking at his watch until the media needed something to point to, and Reagan's "there you go again" defined nothing except something established decades before, that he can handle himself on camera, and so on. You're falling into that same TV-mentality by trying to pick a "moment" when such moments are of no value except to media talking heads who need an angle on a story that doesn't have one angle.
Either way, thanks and good night.