In their final conversations during the transition, Barack Obama issued a stark warning to Donald Trump: North Korea presents the most urgent, alarming, and bedeviling threat you will confront as head of the free world.

• Today, North Korea showed why: The regime claims to have successfully tested a missile that could carry a nuclear bomb and hit Alaska (Update: U.S. officials now believe it may have been that type of missile; Secretary of State Tillerson condemns launch as "escalation.")
• Trump's tweets: "North Korea has just launched another missile. Does this guy have anything better to do with his life? Hard to believe that South Korea ... and Japan will put up with this much longer. Perhaps China will put a heavy move on North Korea and end this nonsense once and for all!"
• What North Korea said, via AP: "[T]he test of an ICBM — the Hwasong-14 — marked the 'final step' in creating a 'confident and powerful nuclear state that can strike anywhere on Earth.'"

This doesn't mean the United States faces an imminent threat, because intelligence suggests the regime is a ways from getting the technology right to shoot a missile with sufficient distance and nuclear capacity. But this is a huge deal and here's why, from the N.Y. Times:

The path of the rocket, via an AP graphic:

Go deeper: Axios Expert Voices charts five courses of action for the U.S. confrontation with North Korea.