Consider this comment that then-CIA Director, soon-to-be secretary of state, Mike Pompeo made last Sunday to Margaret Brennan, host of the CBS News program “Face the Nation.” Pompeo compared the deal Trump hopes to make with North Korea to the bargain Barack Obama and others struck with Iran:

“Most importantly the conditions are very different. The previous administration was negotiating from a position of weakness. This administration will be negotiating from a position of enormous strength with sanctions that are unrivaled against the North Korean regime.”

Many Americans think of these two countries simply as “rogue states,” the surviving two-thirds of George W. Bush’s “axis of evil,” but there are big differences between Iran and North Korea. In fact, Pompeo’s comparison between them isn’t one Trump should want us to make, because North Korea will be a much tougher problem to crack than Iran was — for any president. Why?

• North Korea already has nuclear weapons. Iran doesn’t.
• North Korea has enough military power without nuclear weapons to kill millions inside the borders of US allies. Iran doesn’t.
• Kim likes isolation. His regime’s survival depends on his ability to isolate 25 million North Koreans from the rest of the world. Iran can’t afford isolation, because its long-term stability depends on the ability of Iran’s economy to deliver improved standards of living to the country’s 80 million citizens. That makes Iran much more vulnerable to sanctions than North Korea, because isolation chokes economic growth.
• Kim will be watching how Trump handles the Iran deal. If Trump shreds it — or keeps threatening to do so — Kim will have reason to doubt he can ever commit to any agreement that Trump, or a future US president, might tear up.