WASHINGTON ― When North Korean leader Kim Jong Un warned in early January that his country was in the “final stages” of preparing an intercontinental ballistic missile, President-elect Donald Trump tweeted, “It won’t happen!”

On Tuesday, Kim blew through Trump’s red line and tested an ICBM capable of reaching Alaska, perhaps with a nuclear bomb. The launch, conducted as Americans were preparing to celebrate their country’s independence, showcased North Korea’s dramatic nuclear weapons development and signaled that Trump’s concept of “maximum pressure and engagement” was failing to deter the rogue state.

North Korea has launched more missiles in 2017 than it did the entire previous year. Meanwhile, the Trump administration has struggled to articulate a coherent strategy toward the Korean Peninsula.

Part of the administration’s problem is that there are no attractive policy options for dealing with North Korea. A pre-emptive military strike would only set back, rather than destroy, Pyongyang’s nuclear program and would almost certainly prompt retaliation against the densely populated capital city of South Korea, a key U.S. ally. A decapitation strike aimed at removing Kim himself would be high-risk and unlikely to succeed since the North Korean ruler has systematically killed those who might have been looking to replace him.

U.S. military leaders in charge of drawing up war plans have warned against rushing into an armed confrontation on the Korean Peninsula. “A conflict in North Korea … would be probably the worst kind of fighting in most people’s lifetimes,” Defense Secretary James Mattis said in May.

Diplomatic talks now could help avert the risk of a nuclear war, but are unlikely to compel North Korea to surrender its nuclear weapons arsenal.

This puts the U.S. in an uncomfortable position. “The North Koreans decided that if they build nuclear weapons, we’re going to have to learn to live with it,” said Jeffrey Lewis, director of the East Asia nonproliferation program at the Middlebury Institute of International Studies at Monterey. “And I think they’re right.”

The North Koreans decided that if they build nuclear weapons, we’re going to have to learn to live with it. And I think they're right. Jeffrey Lewis, of the Middlebury Institute of International Studies at Monterey

Trump’s inability to deter Pyongyang’s nuclear ambitions is not unique. Since the collapse of a U.S.-North Korea nonproliferation agreement in 2003, successive U.S. presidents have failed to persuade North Korea to give up its nuclear weapons program in exchange for economic relief and international legitimacy. If anything, Pyongyang has become even more wedded to it since watching the U.S. help overthrow Muammar Gaddafi after the Libyan leader surrendered his nuclear weapons program.

“They’re dealing with the fact that they have the same unpalatable options their predecessors had,” Eliot Cohen, a State Department official during the George W. Bush administration, said of Trump’s team.

But if North Korea’s nuclear program has proved intractable for past presidents, Trump is particularly ill-suited to deal with the problem. The president has little foreign policy experience and has left top diplomatic posts unfilled. He has said he likes to be unpredictable and is internationally known for his uncensored, stream-of-conscious Twitter rants.

“North Korea has just launched another missile. Does this guy have anything better to do with his life?” Trump tweeted after the ICBM launch, referring to Kim. “Perhaps China will put a heavy move on North Korea and end this nonsense once and for all!” he continued.

Those who have spent years pursuing diplomacy with Pyongyang worry that a careless move from the U.S. president could derail the fragile status quo.

“I don’t think he puts enough thought into how the North Koreans are going to consume his tweets. There’s a lot of room for misinterpretation,” said Suzanne DiMaggio, a senior fellow at the New America Foundation who has participated in nongovernmental diplomacy with North Korea officials.

While Trump made North Korea a high priority even before taking office, his approach has been erratic. During the campaign, he praised that country’s young leader for consolidating power by executing his uncle. “You gotta give him credit,” Trump said at a campaign rally in January 2016. “I mean this guy doesn’t play games. And we can’t play games with him.”

During his first official trip to Asia in March, Secretary of State Rex Tillerson announced that the Obama-era policy of “strategic patience” ― isolating North Korea but refraining from using force or seeking concessions ― had ended. “All options are on the table,” Tillerson warned, without elaborating on the new administration’s policy.

President Trump initially tried to convince Chinese leader Xi Jinping to take the lead role in ending North Korea’s nuclear efforts – in part by hinting at economic concessions to Beijing. He later said that a conversation with Xi had taught him that the fraught centuries-long history between the two Asian neighbors would make that difficult. “After listening for 10 minutes, I realized it’s not so easy,” Trump told The Wall Street Journal in April.

When confronted with Kim’s escalating actions, the Trump administration appeared caught off-guard. Following an April 4 missile test by North Korea, Trump didn’t tweet or issue a formal statement about it. Tillerson offered an ominous three-sentence message: “North Korea launched yet another intermediate range ballistic missile. The United States has spoken enough about North Korea. We have no further comment.”

By June, Trump seemed to have abandoned his policy of working with China to rein in North Korea. “While I greatly appreciate the efforts of President Xi & China to help with North Korea, it has not worked out. At least I know China tried!” he tweeted.

On Wednesday, the day after the ICBM launch, Trump went even further and blamed China for North Korea’s rising nuclear capability. “Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us - but we had to give it a try!” he tweeted.

The White House and the State Department did not respond to requests for comment on how the latest missile launch would affect U.S. policy.

Nikki Haley, the U.S. ambassador to the United Nations, warned on Wednesday that North Korea’s actions were “quickly closing” off options for a diplomatic solution and that the U.S. “will look at any country that chooses to do business with this outlaw regime.”

DiMaggio, who met with North Korean officials in May, said the Trump administration should respond to the ICBM test by making “a good faith effort at diplomacy.” North Korea’s rapid nuclear development should be viewed as an effort to improve its negotiating position before coming to the table, she said.

“Based on the conversations I’ve had with North Koreans, denuclearization would not be on the table initially, but that could change over time,” DiMaggio said. “The best bet for the U.S. would be to pursue some type of freeze agreement to at least decrease the heightened sense of tension that we’re currently experiencing.”

Others who have worked on North Korean issues are skeptical of negotiations aimed at merely halting its nuclear program at current levels. “North Korea would be happy to have a freeze,” said Robert A. Manning, a former U.S. intelligence official who is now at the Atlantic Council, an international affairs think tank. A freeze, he said, would provide Pyongyang with de facto recognition as a nuclear power.

Manning prefers a strategy of leaning on China to freeze North Korea out of the international system. But he also recognizes that the U.S. might have to learn to live with a nuclear-armed North Korea. In 1964, he said, the idea of a nuclear armed-China made Americans hysterical.

“But we learned to live with it,” he said. “As far as I can see, deterrence works.”