If, as we’ve come to believe over the course of the summer of Donald Trump, that nothing he says, no matter how inappropriate, misogynist, thuggish, misleading or just plain dumb, will ever be held against him, then the Donald’s interview on Hugh Hewitt’s radio show yesterday won’t count for much. After all, what did it matter that he apparently had never heard of the names of the various leaders of terrorist groups and didn’t know the difference between the Kurds and the Iranian terrorist Quds force? If you’re a magical politician who thinks you can transform both the American government and the world by the force of your personality, details don’t matter. And if he screws up questions that indicate he’s blowing smoke on foreign policy, then, no doubt, many of his fans will simply join him in trashing Hewitt as “a third-rate radio announcer” as he did today on “Morning Joe.” But before we merely file this away story along with all the other instances in which Trump exposed himself as a blowhard or buffoon without having that hurt his popularity a bit, it’s appropriate to reflect that knowledge of foreign policy isn’t a matter of “gotcha” questions, it’s primarily what we hire presidents to do. And if you can’t be bothered to study up on the details, then even a seeming political colossus like Trump needs to be reminded that the Herman Cains of the world don’t’ get elected president.

Listening to the tape of Trump’s interview with Hewitt, it’s hard not to compare him to Cain, whose unsuccessful presidential candidacy was something of a trial run for the current season of the outsider. Cain is chiefly remembered for having a few weeks at the top of the polls in the fall of 2011 before he crashed and burned even before Iowa. But before that, he shamelessly exposed himself as a foreign policy ignoramus by flubbing a series of questions on various world crises and issues. In truth, he knew a lot less than Trump does, so in that sense the analogy is unfair. But what they did have in common was a sense that it didn’t really matter. Trump’s breezy dismissal of his failure to have this information at his fingertips is very much like Cain’s insistence that he could study up about it at his leisure. Trump’s insistence that he will simply order things to be done right and that magically all will be well may impress his fans. But saying, as he did, that “I will be so good at the military, your head will spin,” is no substitute for actually knowing you’re talking about.

What’s odd about this is that competence and smarts are supposed to be at the core of Trump’s appeal as he rises above career politicians who have lost our collective confidence. But you can’t be competent or smart without knowledge. It’s one thing to pose as an economic expert on domestic issues, but though this is often forgotten in presidential campaigns where all candidates pretend that presidents can control the economy, foreign policy is the one aspect of our government on which they more or less have carte blanche.

So it is no small thing when presidential candidates haven’t bothered to learn the facts and the names about foreign policy issues. To her credit Carly Fiorina, who is also not a career politician, was asked the same questions by Hewitt and aced them the same day. That doesn’t guarantee that she’ll be a great or even a good president but at least it shows she is willing to expend the effort to learn about these topics rather than to pontificate about them as Trump does without any grounding in reality.

While his rivals will chortle about it and those who like him will dismiss this incident the way they dismiss anything that shows him in an unfavorable light, the real problem isn’t the mistakes he made with Hewitt, who once again proved that he is one of the few radio talkers who asks tough, detailed questions of everyone who comes on his show. Rather it’s Trump’s belief that by merely saying he will fix things that his force of personality will make this so. In that sense, the proper analogy here isn’t with Cain but with Barack Obama.

Obama also told us that he could fix the world without supplying too many details. Granted, Trump hasn’t yet told us that he will turn back the oceans as Obama did but when you listen closely to the Donald blithely speaking of building walls and making other countries pay for them or that he will simply out-negotiate the Chinese or order the Middle East to behave properly, it’s another version of “hope and change.” Trump is a different kind of messiah but his mantra about greatness isn’t much different than Obama’s empty promises. At the bottom of both is a belief that ego-driven pronouncements count more than intractable facts.

Trump doesn’t appear bothered by his latest foolishness and, given his success in spite of previous and perhaps even worse mistakes, who can blame him? But the Hewitt interview ought to scare him. It’s a long campaign, and anyone that believes they can blow smoke the whole way without paying a price is bound to eventually learn that doesn’t work. Trump is no Herman Cain, but he may be another Obama. But unlike Obama, Trump doesn’t have the luxury of an adoring press corps that will cover for him. Will conservatives who wish reporters would be tough on Obama continue to echo mindlessly Trump’s insults of journalists likes Hewitt and Megyn Kelly who try to hold him accountable? Maybe. But those who complain about “gotcha” questions when they are exposed as blowhards don’t always get away with it. Obama fooled the American people, but he had other historic reasons for voters to embrace him. They may not fall for it again.