The risk of an all-out war with North Korea is one reason a military strike isn't likely at the top of the possible responses to the North's latest missile test.
U.S. officials worry that retaliation by the North could lead to untold numbers of deaths in South Korea.
Still, President Donald Trump isn't taking the threat of a missile strike off the table. He said Thursday that he is weighing "pretty severe things" as North Korea continues its missile tests and nuclear program.
Defense Secretary Jim Mattis tells reporters that this week's test-launch of an intercontinental ballistic missile doesn't threaten the U.S. The Pentagon chief also says that the latest test doesn't bring the U.S. closer to war.