In his speech before the U.N. General Assembly on Tuesday, President Trump triggered gasps in the building when he declared if the United States “is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea.”

Not just decapitate the regime — destroy the entire country of 25.4 million people.

“Rocket Man is on a suicide mission for himself and for his regime,” Trump added, in a mocking reference to North Korea’s leader, Kim Jong Un, who has conducted missile tests in recent months, including a July test of an Intercontinental Ballistic Missile that experts say could put all West Coast cities and others in range if the trajectory is tweaked. The CIA has also reportedly concluded that North Korea has figured out how to attach a nuclear payload to the missile.

It is difficult to parse what this administration’s North Korea policy truly is, given the conflicting statements made by officials. Does Trump see a military strike as the preferred way to resolve the North Korea nuclear program or as a last resort? Does he just like appearing tough? Who knows? But the world — and especially we here in California — should be concerned.

U.S. presidents in the past have stated the obvious: that the United States has the ability to destroy North Korea. That is why some foreign policy analysts like the Washington Post’s David Ignatius interpreted Trump’s bluster as a “restatement of the existing U.S. policy of nuclear deterrence.”

But Trump’s remark, for me, went beyond that. It was dangerous both because of how he is perceived abroad — as a reckless, bombastic leader with no strategy or understanding of the Korean Peninsula’s history or geopolitics — and because North Korea’s capabilities have advanced since those presidencies.

Trump makes things worse by needlessly boasting of American military might. Near the start of his UN speech, he reminded the world that the U.S. Senate just approved $700 billion in additional defense spending. “Our military will soon be the strongest it has ever been,” he exclaimed.

Meanwhile, the State Department’s Bureau of East Asian and Pacific Affairs — the office that would normally coordinate with our allies during times of heightened tension with North Korea — still only has an acting assistant secretary of state. Trump has not named an ambassador to South Korea yet, either, signaling that diplomacy isn’t a priority.

Trump’s declaration also follows his August warning that “North Korea best not make any more threats to the United States. They will be met with fire and fury like the world has never seen.”

At the time, analysts played down the significance of the remarks as typical off-the-cuff bluster spouted at his Bedminster, N.J., golf club. Now that he has read the threat off a teleprompter before all the nations in the world in a speech that was presumably vetted by others in his administration, it will be treated more seriously abroad.

“You shouldn’t be talking about destroying a nation,” Scott Sagan, the Caroline S.G. Munro Professor of Political Science at Stanford University and senior fellow at Stanford’s Center for International Security and Cooperation,ss told me. And “why is he using this term ‘rocket man’? Sort of a bully’s way of diminishing your adversary.”

The effect? Rather than deter Kim, Sagan said, Trump has “created increased incentives for North Korea to get even greater military capability.”

Sagan knows the risks here. He literally wrote the book on near-disasters involving nuclear weapons. In a recent piece in Foreign Affairs, he argued it was “time for the U.S. government to admit that it has failed to prevent North Korea from acquiring nuclear weapons and intercontinental ballistic missiles that can reach the United States” and to focus on deterrence. U.S. officials in the White House and the Pentagon “face a new and unprecedented challenge,” he warned. “They must deter North Korean leader Kim Jong Un while also preventing U.S. President Donald Trump from bumbling into war.”

Sen. Dianne Feinstein, D-Calif., was also alarmed Tuesday at the prospect of conflict. She was one of the first legislators to issue a statement condemning Trump’s “bombastic threat to destroy North Korea” and for using the United Nations — a body intended to foster global cooperation — as a “stage to threaten war.”

Trump said “the United States is ready, willing and able” (to destroy North Korea) but hopefully this “will not be necessary.”

He urged the United Nations to further isolate North Korea so it would give up its nuclear program, a message applauded by his Republican allies. “That’s what the United Nations is all about, Trump said. That’s what the United Nations is for. Let’s see how they do.”

Let’s see how they do? The United States, the most powerful nation on Earth, is supposed to formulate strategies and lead. When I covered the State Department for Bloomberg News, I watched Secretary of State Condoleezza Rice convene endless, difficult multiparty negotiations to try to dismantle North Korea’s nuclear program. They failed. But now that North Korea has nuclear capabilities, U.S. leadership is ever more critical to preventing their use. North Korea wants assurances the United States isn’t planning to obliterate it. Instead, Trump has just given more reason to fear that is the plan.

Janine Zacharia, a former Washington Post foreign correspondent, teaches journalism at Stanford University.