There are valid cases against the Iran nuclear deal: that it legitimizes Iran's violent regime and its growing power in the Middle East, that it could leave us all worse off if it falls apart, that it would be difficult to reimpose economic sanctions.

There are also bad cases against the Iran nuclear deal: that war is preferable, that the Iranian "mullahs" are incapable of human rationality and thus will not respond to incentives, that President Obama is a naive weakling whose obvious cowardice can only embolden the Iranians (never mind that he got Iran to willingly surrender most of its nuclear program).

And then there is what may be the worst case against the Iran deal, or at least the worst that a major political figure has made. Jeb Bush, on Monday night, explained to a pro-Israel group that he opposes the nuclear deal — yes, hours before the terms had even been revealed — because he said you should never, ever negotiate with dictators.

Bush's case was simple: Negotiating with dictators is appeasement and never works. Here's the quote, which his campaign tweeted with the message "we should walk away":

History is full of examples of when you enable people or regimes that don't embrace democratic values, without any concessions, you get a bad result. It's called appeasement.

"Never negotiate with dictators" sounds nice if you live in a parallel dimension where the only dictator who ever existed was Adolf Hitler. But it turns out that's not the case. Not only that, but America actually negotiates with dictators all the time. Some of those dictators are even our allies! Take Saudi Arabia, for example, which we not only negotiate with but sell lots and lots of military equipment to.

Jeb Bush should know this better than anyone: Both his father and his brother were straight-up pros at negotiating with dictators during their presidencies. In fact, both of them negotiated nuclear agreements with dictators — and those agreements worked out really well.

President George H. W. Bush helped oversee two rounds of the Strategic Arms Reduction Treaty (START) with the Soviet dictators. President George W. Bush negotiated a nuclear deal with Libyan dictator Muammar Qaddafi in 2003. For the Bushes, "We love negotiating nuclear deals with dictators" is practically on the family crest.

And those nuclear agreements all worked out quite well. The Soviet Union did not surrender nearly as much of its nuclear program as Iran did this week, but it did dismantle thousands of nuclear weapons, which was pretty great. Qaddafi gave up his entire nuclear program, more than Iran did, but he also didn't submit to the kind of rigorous verification procedures Iran will go through. Later in his time in office, the George W. Bush administration actually put forward a crazy idea: that the US should negotiate a nuclear deal with the dictators of Iran as well.

The point is that, if you grew up in the Bush family, you are immediately related to some people who can tell you firsthand how awesome it is to negotiate nuclear deals with dictators, and who have very strong track records to back that up.

It might be easier to take Jeb Bush's opposition to the Iran deal seriously 1) if he had announced it after the details came out, rather than before, and 2) if he were not basing his objections on a simplistic idea that flies in the face of how both his brother and father conducted foreign policy. A lot of people are probably opposing the deal for political reasons rather than actual foreign policy calculus, sure, but he could try to be a little less transparent about it.