PRESIDENT TRUMP’S unsettling threat Tuesday aimed at North Korea was reckless and unnecessary. In its bombast, it resembled nothing so much as Kim Jong Un’s regular denunciations of the United States, frantic and hyperbolic. Why would the president of the world’s most powerful nation want to descend to that level?

At an event at his New Jersey golf club, Mr. Trump declared, “North Korea best not make any more threats to the United States. They will be met with fire and fury and frankly power, the likes of which this world has never seen before.” To raise the specter of nuclear war — and to do so to ward off mere threats, at that — is to draw a red line in the most foolish and destabilizing manner.

Since nuclear bombs were dropped on Hiroshima and Nagasaki seven decades ago, they have not been used in combat. Still, the danger that they will be used again has never disappeared; the years since the end of World War II have been filled with false alarms and close calls, which could easily recur. The United States and Russia keep thousands of nuclear missiles on launch-ready alert, meaning they are ready to launch within minutes of a president giving the order. Adversaries know this. Mr. Trump’s threat of “fire and fury” may sound like hype to American ears, but the words could be heard quite differently by others, such as Mr. Kim, the belligerent leader of a nuclear North Korea. Mr. Trump’s language could easily be misunderstood — he didn’t say precisely what would lead to “fire and fury” except for North Korea’s “threats”— and the upshot could be miscalculation or, heaven forbid, the kind of accidental entry into conflict that has haunted the globe since the dawn of the atomic age.

[This is the moment of truth on North Korea]

(Reuters)

The U.S. nuclear arsenal is kept in harness for one purpose only: deterrence. The definition of deterrence is a credible threat of retaliation that would prevent an adversary from attacking. Credibility, the essence of deterrence, means the other side has to believe the threat is real. It flows from maintaining a modern and capable force, not from boasts or threats. “We should not be engaging in the same kind of blustery and provocative statements as North Korea about nuclear war,” said Ben Cardin (Md.), ranking Democrat on the Senate Foreign Relations Committee. “No one should think that a conflict with North Korea will be a quick little glorious war, or be tempted by false hopes that North Korea’s nuclear program can be destroyed with a single antiseptic surgical strike.”

[Rex Tillerson just erased the reckless red line Trump drew on North Korea]

North Korea’s steadily advancing nuclear weapons and missile programs are serious; The Post reported Tuesday that intelligence officials believe the Pyongyang regime has successfully miniaturized a nuclear warhead to fit on a missile, the next step in a weapons system that could hit the United States. Dealing with that will require patient pressure and skilled diplomacy, perhaps for years. Instead, Mr. Trump has strut into the arena with a jarring rhetorical grenade.