After months of venomous barbs and apocalyptic threats of war, the meeting between President Trump and the North Korean leader, Kim Jong-un, was unquestionably a relief, with its handshakes and effusive politeness.

Mr. Trump deserves credit for setting in motion a process that for the time being will keep the two adversaries talking to each other. But the statement he signed with Mr. Kim was strikingly spare, with little evidence of any substantial progress despite Mr. Trump’s claim that it was “comprehensive.”

For now, all we know is that Mr. Trump has made major concessions, while Mr. Kim made fewer commitments than North Korea has made to past administrations and merely reaffirmed a goal of “denuclearization” that North Korea first announced in 1992. For his part, Mr. Trump announced he would provide North Korea with security guarantees and suspend joint military exercises with South Korea. As he gushed about the virtues of the North Korean dictator, just a day after he savaged some of America’s closest democratic allies, he even endorsed the North Korean view of such joint exercises as “provocative.”

Yes, the meeting deserves to be described as historic, and the president clearly reveled in the political theater of doing something none of his predecessors did — meeting a North Korean leader and proclaiming a new era between two countries that have been enemies since the Korean War. He also delighted in once again presenting himself as a deal maker: tackling one of the world’s most intractable security challenges, the threat of North Korea’s arsenal of up to 60 nuclear weapons and the missiles on which to deliver them.