Fears of a North Korean missile crisis

North Korea has promised a “Christmas gift” to the United States if no progress is made on lifting sanctions. That may be shorthand for a test of an intercontinental ballistic missile — and it could produce a particularly dire cycle of crisis.

If the launch happens, it could signal that the North Korean leader, Kim Jong-un, does not expect Washington to lift the crushing sanctions it has imposed on his impoverished nation anytime soon. Estimates suggest that the North has been increasing its missile arsenal since Mr. Kim met President Trump for the first time 18 months ago.

Calculus: The United States would probably respond to a launch by reverting to its old strategy of lobbying the United Nations Security Council to tighten sanctions. But Mr. Kim could coax China and Russia, which are both eager to reassert a leadership role on the North Korea issue, into loosening them instead. He may also calculate that impeachment has weakened Mr. Trump.