Long story short: Trump is a fascist, but it was the actions of people like Nixon and Reagan that made a fascist like Trump inevitable by dealing untold and irreparable damage to the social and economic checks keeping the system from destroying itself. Kissinger was his own brand of evil, aiding in the killing of anywhere from hundreds of thousands to millions. Suffice it to say that in no time period did America ever lack for absurd amounts of evil; the only difference was that the system and the people manning it had not yet lost the ability to defend their preferred kind of evil.

PS: I'm not trying to defend the US constitution; that document is beyond saving for many reasons, but any system will fail to maintain itself when the people manning it aren't willing to defend it.