Obviously, if Trump were a straight-A student who aced his SATs, he would have been more than happy to have those records made public. But why would it have mattered so much even if he wasn't? Who would really care whether a man in his 70s got a C in history class a half century ago?

It's more than just embarrassment. The answer lies in the narrative Trump was writing, not just about himself but about Obama and the entire American system.

That narrative told white voters that their resentments and disappointments were both perfectly valid and not their fault. When Trump told them that the system was "rigged" against them, he wasn't talking about wealth and power. He was talking about white people supposedly being held back, by immigrants and undeserving black people who had been pushed ahead of them to the front of the line.

Central to that picture was the idea that Barack Obama was the most undeserving of all. Trump turned himself from a reality show character to a political figure by becoming the country's most prominent advocate of birtherism, the racist theory that Obama was not a real American but in fact had been born in Kenya.