Three weeks before becoming president, Donald Trump weighed in on the threat of North Korea developing a nuclear warhead capable of reaching the U.S. "It won't happen," he vowed on Twitter.
Now planners are contemplating what a U.S. strike to prevent that development might look like, and the options are grim.
Analysts estimate North Korea may now possess between 10 and 25 nuclear weapons, with launch vehicles, air force jets, troops and artillery scattered across the country, hidden in caves and massed along the border with South Korea. That is on top of what the U.S. estimates to be one of the world's largest chemical weapons stockpiles, a biological weapons research program and an active cyberwarfare capability.