Jeb Bush has worked in politics for 35 years, and has been a potential presidential candidate for at least 10, but there's still so much he doesn't know. He doesn't know what's causing climate change. He doesn't know whether the Iraq war was a good idea. He doesn't know if a racist shot up a church because black people were in there. There's something a little odd about running a "Who's to say?" campaign for a job that by definition answers that question with "me."

On Friday, Bush said of the Charleston church shooting, “I don't know what was on the mind or the heart of the man who committed these atrocious crimes. But I do know what was in the heart of the victims.” We don't have all the facts about this terrible crime. But the alleged shooter, Dylann Roof, appears to be an open book. He wore the flags of the racist governments of Rhodesia and apartheid South Africa. He used racial slurs. He said he wanted to start a "civil war." So while Jeb is technically right that you can never know exactly what's in another person's head at any moment, there's enough evidence of Roof's motivations to hazard a guess. But not Jeb, not even when a Huffington Post reporter caught him in a hallway and pressed him on the question:

Huffington Post: Mr Bush do you believe the shooting was racially motivated? Bush: It was a horrific act and I don't know what the background of it is, but it was an act of hatred. Huffington Post: No racially motivated? Bush: I don't know! Looks like to me it was, but we'll find out all the information. It's clear it was an act of raw hatred, for sure. Nine people lost their lives, and they were African-American. You can judge what it is.

You can judge, just please don't make Jeb Bush do it!

In many cases, admitting your own ignorance is an act of bravery. For Jeb Bush, it's probably the opposite. Today's Republican presidential candidate has to take conservative positions to win the nomination and then, just a few months later, moderate them to appeal to swing voters. So you could imagine he might see an advantage in a different tactic: claiming you just don't know what to think in the primary and then come to an understanding in the general.

Whatever the reason, "I don't know" is one of Bush's favorite phrases. Here are some of the many things he should probably know about but doesn't.