In a story “The War that Wasn’t”, Peter Baker writes about Donald Trump’s claim that Barack Obama was prepped for a pre-emptive strike against North Korea as if Hillary Clinton would have done it.
In fact, there was a lot talk about a very dangerous “bloody nose attack” (maybe magnetic flux on infrastructure) until at least the Winter Olympics. Mattis had to remain the officially recognized adult in the room for a while. By March 2018 the president seemed much less likely to do it and gradually set up the summit, where he buttered up Kim Jong Un.
Trump has said that placating Kim was necessary to avoid war, which is un-Trump-like behavior generally.