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.

On whether the federal government should enforce laws against marijuana in states that have legalized it:

"In medical marijuana states? I don’t know. I’d have to sort that out." – August 15, 2014.

On whether man is causing climate change:

"I'm a skeptic. I'm not a scientist. I think the science has been politicized." – July 8, 2009.

"I don’t think anybody truly knows what percentage of this is man-made and which percentage is just the natural evolution of what happens over time on this planet." – May 21, 2015.

On whether he would have invaded Iraq, knowing what we know now:

"Yeah, I don't know what that decision would have been, that's a hypothetical." – May 12, 2015

On whether "religious freedom laws" that allow discrimination against gays are a good thing:

“I don’t know about the law, but religious freedom is a serious issue, and it’s increasingly so, and I think people that act on their conscience shouldn’t be discriminated against, for sure." – March 19, 2015.

On whether the Florida legislature should compromise and accept the Medicaid expansion:

"I don't know. That's their job, frankly. Expanding Medicaid without reforming it is not going to solve our problems over the long run." – April 16, 2015.

On whether Hillary Clinton should turn over the private server that stored her State Department emails:

"I don’t know. I don’t know what the laws are. I think being clear and transparent in a world of deep disaffection where people don’t trust folks is the right thing to do." – March 26, 2015.

On a potential Sarah Palin presidential candidacy:

"I don't know what her deal is." – February 24, 2010.

On the quality of his own potential candidacy:

"I have no clue if I’d be a good candidate, I hope I would be." – December 14, 2014.

On the quality of his own potential presidency:

"I think I could serve well as president, to be honest with you. But I don’t know that either." – December 14, 2014.