The forecast is for calm, more calm, and then the storm of the century. You may want a bomb shelter after all.

On Sunday, President Donald Trump took to Twitter to savage the critics of his summit in Singapore on June 12 with Kim Jong Un.

“The denuclearization deal with North Korea is being praised and celebrated all over Asia,” he tweeted. “They are so happy! Over here, in our country, some people would rather see this historic deal fail then give Trump a win, even if it does save potentially millions & millions of lives!”

Trump, like Secretary of State Mike Pompeo, is feeling the heat of criticism over the joint statement signed in Singapore. Many think that vaguely worded document will not lead to the “amazing deal” the president promised the world in his June 12 interview with Voice of America’s Greta Van Susteren.

There is, despite Trump’s vigorous defense, much to be concerned about.

The American president, until three weeks ago, had brilliantly outmaneuvered Kim. Then, surprisingly, Trump began to make what looked like rookie negotiating mistakes, squandering hard-won advantage.

His most recent tactics have been so ineffective—and the break from smart tactics to poor ones so clear—that it appears Trump may have shifted goals from trying to disarm Kim to winning him over instead.

Yet if Trump is still trying to take away Kim’s missiles and nukes, the forecast is a return to the tension that marked most of last year.

“No one has found a way to persuade North Korea to move in sensible directions,” Stapleton Roy, the former U.S. ambassador to China, told me in early 2004. Then, he was correct. This spring, Trump proved Roy wrong.

Through a combination of Trumpian threats to use force and enhanced sanctions, which cut the flow of international payments to the regime by half according to U.S. government estimates, Kim was motivated to make concessions, including releasing three Americans last month and on April 27 making commitments, through South Korean President Moon Jae-in, to give up his nuclear arsenal. Supreme Commander Kim on April 28 also promised the suspension of weapons testing, and he destroyed at least part of the Punggye-ri nuclear testing site on May 24.

Trump, in a brilliant tactical move, withdrew from the planned Singapore summit on May 24, forcing the North Koreans to turn their rhetoric from belligerent to conciliatory in a matter of hours.

Until the days before the summit, therefore, only the North Koreans were making concessions. Trump was pushing them around, almost at will.

Then Trump, being Trump, flopped. Instead of pressing the advantage—what the North Koreans would have done—the president relaxed the pressure.

First, he dropped the various preconditions for talks his administration had announced. That allowed the summit to proceed and gave Kim his first win, the legitimization coming from meeting with the U.S. president as an apparent equal. Having gained his prize, Kim’s incentive to come to terms with Washington fell precipitously.

Second, Trump constantly complimented Kim, almost certainly the result of not only Trump’s general love of superlatives but also his belief it would help win over the North Korean leader.

The flattery was certainly unnecessary. “I’m not sure how that kind of language helps in dealing with Kim,” Tara O of Pacific Forum CSIS told The Daily Beast. O reviewed Rodong Sinmun, the principal newspaper of the Korean Workers’ Party, in the days following the summit and found, surprisingly, the publication made no mention of Trump’s praise.

Trump’s generous words indicate he has misconceived the nature of the Kimist state. Apparently, the president believes that establishing a personal bond with the North’s affable tyrant is the way to entice him to give up nukes and missiles. But even if Kim genuinely likes Trump and has been touched by his laudatory comments, the nature of his regime matters. Kim operates in a system that restricts him from reciprocating friendly gestures.

And, in all probability, Kim and those surrounding him in Pyongyang find Trump’s overly ingratiating comments a sign of unseriousness and a signal of his weakness.

Worse, Kim may even see those words as a hint of Trump’s gullibility. Yes, flattery is a part of diplomacy and over-the-top praise may work in some cultures, but not in the tough Korean one. Koreans, especially those sitting at the top of shaky totalitarian systems, respect strength more than others.

Trump’s salute to a North Korean general in Singapore, revealed in Pyongyang’s 42-minute propaganda documentary, was grossly inappropriate and almost certainly counterproductive for the same reason.

Third, Trump, receiving little in return, made significant concessions. He suspended large-scale joint military exercises with South Korea without getting the North Koreans to suspend their drills. As a result, the Korean People’s Army will go ahead with its summer training cycle and the U.S. and South Korean forces will forego the crucial Ulchi Freedom Guardian exercise in August.

Moreover, Trump effectively relaxed sanctions. Although the president and Pompeo insist they will continue their “maximum pressure” campaign, they have to know they are already giving the North Korean leader de facto relief from the measures. As The Wall Street Journal reported on May 28, the administration held off designating almost three-dozen entities—some of them Russian and Chinese—as sanctioned entities.

North Korea changes front companies all the time, so not sanctioning new ones hollows out the pressure campaign quickly. Once Kim is sure his new dummy companies will not be designated, he will realize he does not need Trump to formally lift the coercive measures.

Moreover, Trump is allowing China to blatantly violate sanctions with impunity. Beijing is already relaxing inspections at the North Korea border. Especially since last March, China has been openly violating U.N. rules, and we can expect Beijing to become even bolder because Trump is not imposing costs for brazen conduct.

So what’s the forecast going forward now that Trump has abandoned the policies that gave him initial successes?

“The most damaging aspect of the summit is having compromised U.S. security by handing Kim a blank check with which to further advance his nuclear capability,” Sung-Yoon Lee of the Fletcher School at Tufts pointed out to The Daily Beast. “Sanctions enforcement will fizzle out, diplomatic pressure will dissipate, and China and South Korea will be empowered to return to generous subsidization of the Kim regime.”

With China once again watching his back, Kim can again revert to belligerence. Furthermore, Trump has now given Kim reason to believe the American president can be played.

We all know what happens when Trump feels he has been played. Just ask Justin Trudeau, the prime minister of a country that runs a trade deficit with the one Trump governs. Trump had no substantial trade grievance against Canada, but an annoyed Trump hit back hard nonetheless at the now infamous G7 in Quebec.

Imagine what an enraged Trump will do to Kim. The United States has overwhelming power it can bring to bear on not only North Korea but also its big power sponsors, China, now plagued by a slowing and debt-ridden economy, and Russia, which is always dependent on energy prices.

The Trump administration, in the words of Pompeo, wants “major disarmament” by 2020.

To attain that, the president will probably have to go back to the harsh tactics and rhetoric that got Kim to the bargaining table in the first place. The only difference between 2017, the year of “fire and fury,” and 2020, is that Kim, having bested Trump in Singapore, is undoubtedly overconfident and can therefore miscalculate.

The next cycle of tension will surely be seen by both sides as the final showdown.