President Trump remains bullish that the North Korea nuclear threat can be contained. Speaking to reporters on Saturday, the president praised the “incredible meeting” he had the day before with a top representative of the North Korean leader, Kim Jong-un, trumpeting the “tremendous progress” the two sides had made.

The optimistic view is that the White House meeting with Kim Yong-chol, a former North Korean intelligence chief and now his government’s lead nuclear negotiator, was indeed productive, and Mr. Trump is on his way to resolving one of the world’s most complex and dangerous nuclear weapons problems.

But a path to that outcome isn’t yet visible to the outside world. North Korea has forgone nuclear tests, missile tests and rhetorical attacks for more than 400 days. That’s an important development. At the same time, however, it continues to produce nuclear fuel, weapons and missiles. It has not denuclearized, as Mr. Trump has demanded.

So, as the two leaders prepare for their second summit (reportedly next month in Vietnam ), the pressure is on the Trump administration to articulate a realistic strategy for achieving a mutually agreed upon outcome.