The question is, when? Not within Germany, not at first. Or at least not to a high enough degree. Unless we simply define as intelligent those who resisted or were Jewish etc., but that would be cheating. The Nazis didn't really get much successful resistance until they openly tried to conquer the world, and I can't fathom how much more they could have gotten away with if they had stuck to annexing Austria and Poland, and had "just" murdered and brainwashed in their "own" territory. There might never be a plaque at Tiananmen square. And last time I checked, Dick Cheney still wasn't in jail. And so on. Either fascism and murder aren't actually a thing intelligent people successfully combine against to keep in check, or they suck badly at doing so.
At any rate, that there was such a monstrosity to defeat in the first place is due to lack of resistance early on, and the major political groups cannibalizing themselves before the Nazis even started attacking and murdering them. And then many intelligent people made an about-turn, too. Hannah Arendt said in an interview that many intellectuals were good at "coming up with something". That is, they adapted and came up with all sorts of elaborate rationalizations. You could say the intelligence of a person didn't determine their resistance to the Nazis, but the complexity of their justifications for not doing so. Just because there were (and are) exceptions doesn't mean it wasn't (or isn't) the rule. As the White Rose wrote in their second leaflet:
> The greater part of its former opponents went into hiding. The German intellectuals fled to their cellars, there, like plants struggling in the dark, away from light and sun, gradually to choke to death.