Typical politicians are dishonest but they accept the premise of honesty. In other words, they care that they can plausibly claim to be honest. They form lies in ways to attempt to get away with it and be accepted as true.

Trump has no premise of honesty. He doesn't care what's true or not. He doesn't bother lying and hoping to get away with it. He just wants people to play along and he can know who's loyal by who plays along or not.

That's just one of a massive list of distinctions. The short of it is: typical politicians accept the social norms of their corrupt political world. Obama was one of those. Trump, on the other hand, doesn't give a shit about social norms, and that may be one reason some people find him refreshing — too bad that some of the social norms are positive, and throwing it all away is reckless.

Anyway, my pithy initial reply wasn't clear enough, so it works for the joke. But really, Trump is not a typical politician. He's not even anything like a typical real-estate developer.