In a span of a little more than five months, North Korea and the United States have gone from trading verbal insults and mobilizing for war to engaging in vibrant diplomacy. Pyongyang now appears willing to consider eliminating its nuclear weapons and bringing an end to the state of war that has existed on the Korean peninsula since 1950.

Concurrent with this seemingly stunning progress, President Donald Trump has sought to change the rules of the game vis-à-vis Iran, pulling out of a multilateral nuclear accord that everyone (including the United States) agreed Tehran was abiding by. In doing so, Trump appears to be trying to recreate the formula that's worked so well with North Korea—impose stringent economic sanctions while threatening military action should Iran be foolish enough to reopen its nuclear program.

But while Trump and Kim seem to be embracing peace and denuclearization, the devil is always in the details.