President Donald Trump will take center stage tomorrow when he delivers his first address to the United Nations General Assembly in New York. It's an opportunity for Mr. Trump to lay out his ideas about the role the U.S. intends to play in addressing global problems and, equally important, a chance for world leaders to take the measure of a man who has made no secret of his determination to pursue an "America first" policy with allies as well as adversaries. Mr. Trump needs to use the occasion to reassure America's friends of our continued support while keeping the door open to meaningful negotiations with our opponents on a broad range of issues.

The president's speech, and private talks with other heads of state during the week, will touch upon a daunting array of global challenges, from terrorism, the war in Syria and a massive refugee and immigration crisis to the Iran nuclear deal and the looming threat of North Korea's ballistic missile and nuclear weapons programs. There are no easy solutions to any of these problems, but Mr. Trump needs to avoid making them worse by projecting a commitment to statesmanship and diplomacy. This is no time for the petty bickering and schoolyard name-calling that too often have characterized the president's previous musings on foreign affairs.


That's especially true of the dangerous situation developing on the Korean peninsula, where Mr. Trump and North Korean leader Kim Jong-un have been waging an increasingly shrill war of words in recent weeks that raises the likelihood of a catastrophic miscalculation that could plunge both countries into a war neither wants. The threat is compounded by Mr. Trump's seeming inability to refrain from calling into question America's trade relations and military cooperation with its two strongest allies in the region — South Korea and Japan — just at the moment when Mr. Kim has redoubled his efforts to undermine those relationships.

President Trump's injudicious comments have put a smile on Mr. Kim's face just as surely as they have dispirited South Korean president Moon Jae-in and Japanese Prime Minister Shinzo Abe. That's what makes this such a perilous moment.

The U.S. needs to back its military deterrence of North Korea with strong diplomatic efforts, but its diplomacy has been hamstrung by the failure of the Trump administration to fill scores of important State Department positions with qualified appointees who could develop a coherent policy in response to Mr. Kim's saber-rattling. Instead, U.S. foreign policy is being driven almost exclusively by the small group of current and former military men Mr. Trump has appointed to his cabinet.

Meanwhile his administration has spent the last seven months disparaging the UN, undercutting our alliances, and pulling out of just the sorts of multilateral agreements — such as the Paris climate accords and Trans-Pacific Partnership — needed to address global challenges. Meanwhile, Mr. Trump has paired admiration for authoritarian leaders like Russian President Vladimir Putin with evident delight in insulting staunch friends like British Prime Minister Teresa May and German Chancellor Angela Merkel. At times it's hard to escape the suspicion that Mr. Kim and Mr. Putin are merely toying with Mr. Trump, and he doesn't even know he's being played.

Mr. Trump's staff has sometimes managed to keep him on track on signal occasions such as tomorrow's speech, or at least minimize the damage he might do his own or the country's credibility. Nikki Haley, the former South Carolina governor turned U.S. Ambassador to the United Nations, seems to have a keen appreciation for the atmospherics the situation demands, and we trust she and others will seek to steer the president away from the mocking, derisive rants he is prone to whenever he goes off script. Perhaps he should endeavor to say as little as possible in any case and let his aides tackle the big problems quietly behind the scenes. There's no question the UN can and should play an important role in mediating a way through our current dilemmas and that it must do so no matter what Mr. Trump says.

United States President Donald Trump makes his way through diplomats and others after a meeting during the United Nations General Assembly at U.N. headquarters on Monday.
United States President Donald Trump makes his way through diplomats and others after a meeting during the United Nations General Assembly at U.N. headquarters on Monday. (Seth Wenig/AP)

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