As President Trump has implicitly conceded, his approach to the North Korean nuclear threat is failing. It was all about putting the responsibility on China to force the North to abandon its program, which has grown increasingly and alarmingly formidable and now includes as many as 21 nuclear weapons and the missiles to deliver them. “I am very disappointed in China,” he tweeted over the weekend.

Mr. Trump was driven to play the blame game after North Korea on Friday tested an intercontinental ballistic missile that, for the first time, appeared capable of reaching the West Coast of the United States. It marked the second ICBM launch in 24 days and the kind of technical achievement that American presidents said the United States could not tolerate. Mr. Trump, in fact, had insisted in early January that such a missile “won’t happen.”

Well, it did happen — twice. And while experts question how soon a reliable nuclear weapon can be fired on a missile, it is wise to assume that North Korea’s program will continue to advance, putting the United States and its allies South Korea and Japan at greater risk, unless a way is found to break the present cycle of threats and testing.

That cycle persisted over the weekend. On Sunday, in a show of force, the United States flew two B-1 bombers over the Korean Peninsula and conducted a successful missile defense test over the Pacific Ocean. Meanwhile, South Korea said it would soon ask the Trump administration to allow it to build more powerful ballistic missiles that could strike deep into the North.