On the first day of 2017, North Korean leader Kim Jong Un announced that his regime was preparing to test an intercontinental ballistic missile.

Combined with efforts to produce ever-smaller nuclear warheads, the ICBM test would prove a decisive step in Pyongyang’s generational march toward an effective nuclear deterrent—one that could fundamentally change the way the United States, and indeed the whole world, deals with the reclusive North Korean regime.

But Donald Trump, then just weeks before assuming the presidency, promised he’d halt Kim’s test. “It won’t happen!” Trump tweeted.

It did happen. Three times, in fact. Not only did Pyongyang repeatedly test long-range, nuclear-capable ballistic missiles in 2017, it also made significant progress arming its submarines with an atomic weapon.

And the United States failed to stop anything. Trump escalated his rhetoric, even threatening to “totally destroy” North Korea. Meanwhile the Pentagon organized impressive naval war games off the North Korean coast and aerial exercises near the Demilitarized Zone. The U.S. Army consolidated its own forces in South Korea at a sprawling, new mega-base.

But no show of conventional military might, and no late-night angry tweet from America’s commander in chief, could make up for Washington’s self-imposed diplomatic failures. Unwilling to negotiate, the United States watched while North Korea rose. In 2017, Pyongyang became a bigger nuclear power. And Washington became an impotent observer of the results of its own failures.

It didn’t have to be this way. When it comes to slowing the spread of nuclear weapons, history has proved that diplomacy actually helps. Trump either doesn’t understand that or doesn’t care. And that means 2018 likely will see more North Korean missile tests—and more meaningless American rage.

Kim’s third ICBM test of the year, on Nov. 28, was his most impressive. The rocket arced 2,800 miles into space before re-entering Earth’s atmosphere and splashing into the Sea of Japan around 600 miles from the launcher.

David Wright, a physicist with the Union of Concerned Scientists in Massachusetts, calculated the rocket’s potential maximum range. By flattening its trajectory, Pyongyang could extend the rocket’s striking distance to no less than 8,000 miles—sufficient to strike anywhere in the continental United States.

The test also pointed to rapid and systematic advancements on the part of North Korea’s rocket scientists and engineers. A rocket that Pyongyang tested on July 4 had the range to reach Alaska and Hawaii. A July 28 test extended the maximum strike range to include the American Midwest and North Atlantic. With each major test, Kim’s regime got better at lobbing nukes.

Equally worrying, North Korea improved its ability to defend its atomic arsenal from U.S. pre-emptive or retaliatory strikes. In a first for Pyongyang, the November test-launch took place under the cover of darkness, a tactic offering some protection from U.S. air raids. The timing was “the most notable thing,” tweeted Jeffrey Lewis, a nuclear expert at the Middlebury Institute of International Studies in California.

Moreover, the launcher for the Hwasong-14 was mobile. The wheeled “transporter erector launcher” could emerge from, say, one of North Korea’s thousands of underground bunkers, fire its missile, then disappear back into its subterranean refuge—again, offering some protection from American attacks.

That fact was apparently lost on the Trump administration’s allies. “Trump should take out the site where North Korea just launched a missile,” wrote Marc Thiessen, a commentator at the right-leaning American Enterprise Institute in Washington, D.C.

“It wasn’t launched from a test site,” Lewis retorted on Twitter. “That’s the whole point of a mobile missile.”

Trump himself has apparently failed to grasp, or at least acknowledge, the implications of recent developments in North Korea. Asked about Pyongyang’s November test, Trump deflected. “I will only tell you that we will take care of it,” he told reporters.

But “taking care of it” apparently didn’t include any meaningful effort to talk to Pyongyang. A major diplomatic push by the Obama administration in 2015 convinced Iran to give up its own nuclear program. Trump made no effort to duplicate that success. “Time for talk is over,” Nikki Haley, the U.S. ambassador to the United Nations, said of North Korea in July.

At the time of the November test, all the key top State Department posts for dealing with North Korea were vacant. “For the 400th time, I would like to know why we don’t yet have an ambassador in Seoul or an [assistant secretary of state for the Asia-Pacific region],” Alexandra Bell, a former State Department adviser, tweeted shortly after Pyongyang’s ICBM splashed down.

“North Korea’s latest missile test reflects the Trump administration’s failure to craft a coherent strategy,” commented Sen. Ed Markey, a Massachusetts Democrat. “Pressure cannot bring North Korea to a negotiating table that does not exist.”

In mid-December, Secretary of State Rex Tillerson belatedly opened the door to talks with North Korea, saying he wanted the two governments to “sit down and see each other face to face.” But within days, the Trump administration rescinded Tillerson’s offer. “Clearly now is not the time,” a National Security Council spokesperson told CNN.

The Pentagon has tried to fill the diplomatic vacuum surrounding Pyongyang with a host of new initiatives promising military solutions to the North Korean atomic threat. None of them are viable.

In May the Missile Defense Agency tested a rocket it claimed is capable of intercepting an incoming North Korean ICBM before it hits the United States. But the test was, in essence, rigged—the target missile traveled more slowly than a real ICBM does and thus was easier to hit.

Even if the test were realistic, it probably wouldn’t stop Pyongyang from developing better and harder-to-stop rockets, Greg Thielmann, a missile expert and former congressional adviser, told The Daily Beast. “I doubt very much that North Korea would be dissuaded from its current nuclear and missile development track by a successful U.S. test.”

The Missile Defense Agency is also considering a plan to send F-35 stealth fighters over North Korean launch sites in order to shoot down ICBMs in the seconds after they lift off.

But the planes would have to patrol 24 hours a day over North Korea to have any chance of catching a surprise launch. “How do you get the F-35s in there safely?” asked Laura Grego, a missile expert with the Massachusetts-based Union of Concerned Scientists. “I think you would have to already be occupying North Korea to use it,” Grego said of the plan.

If Trump is counting on military measures to make up for diplomatic shortfalls and somehow persuade Kim to give up his nukes, he might want to listen to his own disgraced former adviser Steve Bannon. “There’s no military solution here, they got us,” Bannon told The American Prospect.

“We don’t have to like it, but we’re going to have to learn to live with North Korea’s ability to target the United States with nuclear weapons,” Lewis tweeted.

Having spent 2017 refining his land-based ICBMs, it’s possible the North Korean leader could soon shift his focus to sea-launched ballistic missiles, or SLBMs. “I would not be surprised to see a new North Korean SLBM flight test in the coming weeks,” Ankit Panda from the Council on Foreign Relations predicted on Dec. 11.

Expect Kim’s atomic arsenal to grow only more powerful in 2018. And Trump’s weakness to only deepen.