In three words of a tweet this week, U.S. President-elect Donald Trump vowed North Korea would never test an intercontinental ballistic missile.
"It won't happen!" Trump wrote after North Korean leader Kim Jong Un said on Sunday his nuclear-capable country was close to testing an ICBM of a kind that could someday hit the United States.
Preventing such a test is far easier said than done, and Trump gave no indication of how he might roll back North Korea's weapons programs after he takes office on Jan. 20, something successive U.S. administrations, both Democratic and Republican, have failed to do.