Editor's Note: (Frida Ghitis, a former CNN producer and correspondent, is a world affairs columnist. She is a frequent opinion contributor to CNN and The Washington Post and a columnist for World Politics Review. The opinions expressed in this commentary are her own.)
(CNN) If America's allies in South Korea were already worried that President Donald Trump was about to unleash fire and fury like the world has never seen in their neighborhood, they will find the latest news of Trump's head-snapping reversal on North Korea far from soothing.
The President announced Thursday that he would accept North Korean dictator Kim Jong Un's invitation to meet by May.
It is conceivable that Trump could wring positive results from such a meeting. But it is just as possible that he will agree to a deal to reduce America's presence in the region in exchange for North Korean concessions. That would be a disaster for America's allies and highly gratifying for China and Russia, who would delight in seeing Washington's global footprint shrink, particularly in that part of the world.
But it would also be terrible news for South Korea. It would not only please US rivals at the expense of its friends, but it would constitute a huge loss for America's role as guarantor of global stability, while sparking a new nuclear arms race.
When Trump was running for president, South Korea was already alarmed by what he was saying. After he won, then-acting South Korean President Hwang Kyo-ahn said, "We have been preparing for all possibilities," adding that a worried Seoul contacted the Trump team more than 100 times during the campaign.
They had reason for concern.
In January 2015, before the official launch of his campaign, Trump told an Iowa audience about how disturbing he found it that every time he bought television sets they came from South Korea. In rambling remarks he juxtaposed trade and defense: "Whenever they [South Korea] have a problem we send the battleships...What are we doing; why aren't they paying us?"
Once the campaign started, Trump cast doubt on his commitment to South Korea's defense, suggesting that South Korea and Japan should consider developing their own nuclear weapons, and stating that if they didn't he would be willing to withdraw US forces defending them.
The words propelled the debate in Japan about whether it makes sense, amid a growing threat from North Korea and an increasingly assertive China, to preserve the country's pacifist constitution and rely on the US for defense.
In South Korea, the push to develop nuclear weapons also gathered steam.
In a recent Gallup Korea poll, 60% of South Koreans said it's time to build nuclear weapons. A similar percentage says it opposes a pre-emptive American strike on the North, even as Kim continues building up his nuclear arsenal.
Once in office, Trump reassured South Korea of his commitment, as he launched his bizarre barrage of insults at Kim, warning that he has the bigger "nuclear button" and that negotiating with North Korea is a waste of time. For months the two have sniped, with Trump calling Kim "Little Rocket Man," and Kim parrying with "Old lunatic, mean trickster and human reject" from the North.
South Korean voters elected President Moon Jae-in in hopes that he will be able to help avert war, but that doesn't mean they are reassured by Trump's brash move. Trump has not projected the image of a cautious leader. On the contrary, this new move looks like a risky long-distance throw, flying over the heads of the experts. It could surprise everyone, or fail spectacularly.
For some time now, his over-the-top rhetoric against Kim and his mockery of his own secretary of state's efforts at diplomacy have given South Koreans sleepless nights. Now Trump's unpredictable style, combined with the statements he has made in the past, raise the possibility that South Korea could end up as the biggest loser when the two leaders hold their unprecedented summit.
Kim has already won one round by convincing the President of the United States to grant him the rare honor of a face-to-face meeting. For decades he has sought exactly that, and he achieved it this time for almost nothing in return.
Plan for the meeting immediately strengthens Kim's position at home. With this victory he is even less likely to face a challenge, even though his regime is one of the world's most brutally repressive. Human rights are about to take an even smaller role in North Korea negotiations, if that is even possible.
What matters most, of course, is what kind of a deal Trump might make. One troubling sign is that Trump has lost some of the best minds who could advise him on what is an extraordinarily complex problem. Incredibly, the US doesn't yet have an ambassador in South Korea. The highly respected Victor Cha, formerly of the Bush administration, was withdrawn from consideration.
And the State Department's top Korea expert, Joseph Yun -- the man who brought Otto Warmbier home -- recently retired, depriving Trump of one the country's most knowledgeable authorities.
Trump, of course, is supremely confident in his negotiating skills. We should all wish him success for the sake of the country and the world, because failure could prove disastrous.
The matter of North Korea is deadly serious. The Korean Peninsula was divided at the end of World War II, with the North and South taking sharply different political paths on their respective sides of the 38th parallel. Since then, the North has repeatedly broken across that boundary.
The North's invasion of the South in 1950 triggered the all-out war Americans call the Korean War. And after the war, the Kim dynasty maintained a belligerent stance, trying to assassinate the South Korean President, repeatedly attacking South Korean targets, and emerging as a threat to the world, while brutalizing its own population.
The North's development of nuclear weapons is a grave threat, not only because it makes it possible for Pyongyang to hit other countries, but because it makes defending the South much more difficult. It also perpetuates Kim's vile rule.
Perhaps Trump will pull off some version of a deal of the century, but the odds don't look good. He will be reluctant to walk away without something concrete that he can label a victory. But if a deal involves weakening America's ties with South Korea, he will be ushering in a world order where the US is no longer trusted by its allies, where it is no longer the guarantor of security; one where Russia and China are more powerful, and where the people of South Korea have more reason to lie awake at night.