The Trump administration’s first recourse has been diplomacy. Secretary of State Rex W. Tillerson sought to head off North Korea’s missile program this week by suggesting that the United States could open talks with Pyongyang if North Korea would halt its missile tests.
On Thursday, however, North Korea raised the stakes by saying that it was considering a plan to test-fire four intermediate-range Hwasong-12 missiles in international waters near Guam, home to American air and naval bases as well as a Thaad antimissile system.
Mr. Trump hinted broadly later in the day that he has his own military options in mind. “Obviously we’re spending a lot of time looking at, in particular, North Korea,” he told reporters, “and we are preparing for many different alternative events.”
But few of the military options are straightforward, and some former Pentagon officials involved in war planning for North Korea pointed to the complexities.
A major consideration would be whether and when to evacuate American and other allied civilians, which is no small feat as Seoul, a city of about 10 million, is within range of North Korea’s rockets and artillery and the North Korean military is also armed with chemical and biological weapons.
“With all this talk, what I worry about is a serious miscalculation,” said James D. Thurman, a retired Army general who served as the top United States commander in South Korea from 2011 to 2013. “Before we start talking about all these military…