Trump's signature combination of the ridiculous and the terrifying strikes again.

Donald Trump’s threats against North Korea have moved into a frightening new phase, from overcompensating Twitter play to the planning stages of a provocative military attack.

It seems like ages ago that Trump taunted Kim Jong Un about the size of his “button,” but it was only last week, and the intervening firestorm about Trump’s mental fitness has not slaked his lust for provocation.

According to new reporting from the conservative Wall Street Journal, Trump administration officials are “quietly debating whether it’s possible to mount a limited military strike against North Korean sites without igniting an all-out war on the Korean Peninsula.”

In characteristically Trumpian fashion, the plan even has a trivial bully’s nickname — the “bloody nose” strategy — and features a heavy dose of finger-crossing that North Korea won’t respond by murdering millions of people:

React to some nuclear or missile test with a targeted strike against a North Korean facility to bloody Pyongyang’s nose and illustrate the high price the regime could pay for its behavior. The hope would be to make that point without inciting a full-bore reprisal by North Korea.

It’s an enormously risky idea, and there is a debate among Trump administration officials about whether it is feasible. North Koreans have a vast array of artillery tubes pointed across the demilitarized zone at Seoul, the capital of South Korea, with which they could inflict thousands of casualties within minutes if they choose to unleash an all-out barrage.

As if all of this isn’t frightening enough on its own, consider exactly whom this leak is designed to reach. Past administrations have frequently used press leaks to engage in public diplomacy, to send messages to foreign leaders without changing official policy.

But in this case, Kim Jong Un does not appear to be the audience for this leak. He’s simultaneously unlikely to believe that such an attack would merely be a token strike, and unlikely to care even if he did.

No, this leak appears aimed at making Trump look tough, while also changing the subject from the week of heavy debate about his mental state. Ironically, it was Trump’s threat against North Korea that actually started that debate, a fact that was quickly obscured by the bombshell revelations in Michael Wolff’s book.

But the title of that book, “Fire and Fury,” is itself a reference to yet another reckless Trump threat against Kim Jong Un, one that prompted an earlier round of hand-wringing about his fitness for office.

Trump is obviously trying to change the subject with this reckless leak, but the reality is that this is the subject. Risking millions of lives for the meager benefit of looking tough is the very definition of unstable, and anyone who would entertain such an idea is the very definition of unfit.