I dunno, a lot of people have been saying that Trump withdrawing from the JCPOA shows signals to NK that the US can't be trusted to uphold its agreements. I think that's nonsense, because, really, that's a liability that comes with dealing with *any* democracy, especially the United States. Trump's not the first president to renege on the commitments of a previous president. He's not unique in that respect.
But I'm also not convinced that what Trump has done with Iran and what he's doing in NK are so inconsistent. In general, people haven't considered that after pulling out of the Iran deal Trump might try to renegotiate another deal with Iran -- in part because it's so unlikely and so infeasible that it's a preposterous idea. It's really difficult to imagine it happening. But even if a deal with Iran is DOA, I still do think it's possible that withdrawing from the JCPOA sends a signal to North Korea that's actually conducive to Trump's goals there. I think it says Trump wants what he wants, and if his demands aren't met, he's not going to settle on a bad deal. He's going to walk. It may give him some leverage. After all, North Korea really wants a deal, and the threat it faces if it doesn't make a deal is much, much greater than the threat to the US.
I mean, Trump mentioned North Korea in his speech last night. Someone has thought about this, even if he hasn't.