The gaffe about 'Corporations are People' is fascinating, for many reasons. Obviously he didn't mean it in the sense of the Citizens United decision (which, in effect, declared virtually exactly that). However:
1) The Media that seeks a good story ignores that context and piles on, ironically stoking the Progressives (as if we need any more reasons to roll eye-balls at Mitt). This is unfair to him, of course, but nobody cares since 'knocking off the Front Runner' is the chief sport at this phase of the race.
2) It reveals the world in which Mitt lives, where he honestly does hob-nob with fellow Rich Guys, who all own corporations. He just simply sees them as the People who make up Corporations. Ergo, Corporations ARE People.
3) Didn't John McCain use the 'my friend' rhetorical gimmick a lot, too? Just sayin'.
4) Either Mitt was oblivious to the consequences of such an off-hand statement (which calls into question his qualifications to speak as a President), or he knew what he was saying and didn't care how folks reacted (which calls into question his qualifications to speak as a President), or he honestly subscribes to the notion of Corporate Personhood in its fullest sense (which calls into question his qualifications to speak as a President).
I don't see any way he can escape being branded with this for all eternity. This is Mitt's 'I can see Russia' event, and this fodder for ridicule will scare supporters.
He obviously has enough personal wealth to pursue the goal, but once the common meme is that you are a doofus gets established, your political prospects are in jeopardy. Think Steve Forbes.
Of course, there are exceptions - a former Texas governor comes to mind, although I believe there was eventual consensus reached on him (unfortunately, much too late).
I gotta go.