For the fourth time in two weeks, North Korea has tested an increasingly sophisticated, hard-to-track missile system that could wipe out South Korean and Japanese cities — not to mention U.S. forces based in both countries. Yet Donald Trump says he’s not worried.

The president and his team contend that diplomacy with North Korea remains on track, thanks in part to his personal rapport with leader Kim Jong Un. They say Kim has kept his word by holding off from testing a nuclear weapon or launching longer-range missiles capable of reaching the U.S. mainland.

The risks in that strategy are growing more worrisome as Kim seems increasingly intent on forcing Trump into concessions, critics say — and some members of the president’s own administration privately agree. They argue that Trump is needlessly giving up leverage and may even encourage Kim to cross the U.S. red line on nuclear testing.

“The president has been so vocal and complimentary of Kim refraining from such testing and his own diplomatic ‘success’ that he’s really painted himself into a corner,” said Jung Pak, a senior fellow at the Brookings Institution in Washington. “That also gives Kim leverage: He can threaten privately and obliquely to Trump that he’s thinking about resuming testing to try to goad the president into giving up some concessions.”

While Kim has so far avoided actions that might jeopardize his personal relationship with Trump, he could decide to force a crisis if the administration doesn’t budge. The North Korean leader has given the U.S. until the end of the year to make a better offer, and the regime has said repeatedly in recent weeks that it might reconsider its freeze on more significant weapons tests.

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The recent missile launches show the limits of Trump’s personal diplomacy. When Trump met Kim six weeks ago at the Demilitarized Zone between North Korea and South Korea, he predicted working-level talks would begin in two to three weeks. They haven’t.

Secretary of State Michael Pompeo said Tuesday that the talks could happen in a couple of weeks. He’s said that before.

Kim’s commitment at his first summit with Trump last year remains intact, National Security Adviser John Bolton said this week. The leaders “have an understanding that Kim Jong Un is not going to launch longer-range, intercontinental range ballistic missiles,” he said on Fox News. “The president’s watching this very, very carefully.”

But North Korea has made its dissatisfaction with the lack of relief from devastating U.S.-led sanctions clear through the short-range missile tests and increasingly vocal criticism: The regime has renewed its threat to take a “new road” with the U.S. and warned of a “heavy price” if Washington and Seoul continued to disregard warnings against holding joint military exercises. Bolton has said current drills are “largely computer-driven,” with fewer troops maneuvering than in exercises that Trump ordered halted.

Pompeo has hinted that the U.S. might be sending a sterner message to North Korea privately, while suggesting that North Korea’s missile launches were just part of the diplomatic back-and-forth. Asked at a news conference on Tuesday if the launches sour the environment for talks, Pompeo responded simply, “No.”

In the meantime, the tests of the short-range missile, similar to a Russian system known as the Iskander, show that North Korea is making progress on the technology required to deploy a sophisticated, highly mobile and hard-to-track weapon that could be equipped eventually with a conventional or nuclear warhead and used in a first strike should war break out.

“It’s extremely hard to shoot down and it’s being developed for the purpose of taking out U.S. and South Korean troop concentrations and population centers,” said Evans Revere, a former U.S. diplomat in South Korea. “If that isn’t a threat to the U.S. and its allies, I don’t know what is.”

While South Korean President Moon Jae-in is a strong backer of detente with Kim, tensions with the U.S. remain over cost-sharing for the American troop presence in South Korea. Trump said in a tweet on Wednesday that “talks have begun” for South Korea to take on more of the burden as a “very wealthy nation.” A South Korean official countered that the next round of negotiations on the issue hasn’t yet started.

Trump’s room to maneuver or punish North Korea is limited partly because he’s already imposed what his administration calls “maximum pressure” sanctions against the isolated regime. The only added actions he could really take, such as punishing major Chinese banks that do business with North Korea, would risk major damaging effects on the global economy.

Even publicly, some administration officials have hinted at some distance from Trump’s personality-driven stance on North Korea.

While Trump has scoffed that the North Koreans “really haven’t tested missiles other than, you know, smaller ones,” Bolton has made clear that the tests violate United Nations Security Council resolutions.

Lower-level officials have been more direct about their frustration. In a briefing with reporters during Pompeo’s recent trip to Asia, a State Department official said North Korea’s unwillingness to meet in the time-frame they had laid out wasn’t a positive or constructive response.

The official also criticized the missiles tests, saying that any provocations are unwelcome and that the view among U.S. allies is that North Korea needs to stop them and re-engage in diplomacy.

That reflected the awkward dance that officials have had to perform in honoring Trump’s belief that his personal diplomacy with Kim is working despite the lack of progress toward denuclearization, according to Victor Cha, a senior adviser at the Center for Strategic and International Studies in Washington.

“The president is more and more on his own on this policy,” Cha said. “This is Trump’s show now.”