As the doomsday rhetoric intensifies between two untested and inexperienced leaders in Pyongyang and Washington, the risk of actual combat is rising.
At the United Nations, President Donald Trump shocked most of the U.N. General Assembly by threatening to "totally destroy" North Korea to end the "suicide mission" of its "Rocket Man" leader. North Korea has threatened to create a "sea of fire" in both South Korea and the United States. On Saturday, U.S. B-1 bombers flew close to North Korea's east coast on what the Pentagon said was a mission to demonstrate the military options available to Trump. The U.S. president commented that Kim Jong Un and his foreign minister Ri Yong Ho "won't be around much longer" if they continue their rhetoric.
So what are the military options that the Joint Chiefs of Staff of the U.S. military could put in front of the president?
At the lower end of the spectrum of force, the first set of options would dramatically increase missile defense, both in South Korea and on U.S. territories such as the western Pacific island of Guam. This would include three elements: greater deployment of the Terminal High Altitude Area Defense (THAAD) system, a U.S. anti-ballistic missile system for broad area coverage; more Patriot missile batteries ashore for defense of specific locations; and at-sea Aegis missile defense, which has the best overall kill ratio against incoming targets and extreme flexibility in positioning because it is based on ships that can move nearly a thousand miles a day at speed.
Beyond bolstering missile defense, the Pentagon will look at how to implement a full-blown naval blockade. This would reduce outgoing exports, helping choke the North Korean economy, prevent incoming shipments of oil and oil products, and stop exports of North Korean weapons, a source of cash for the regime. Such a blockade would require a couple of dozen smaller surface ships (destroyers, frigates, corvettes) as well as an aircraft carrier for air cover and a large command-and-control ship to run the complex operation.
Moving up the spectrum, next would be a focused offensive cyber campaign. This would be a non-lethal option, and could be used broadly against North Korean infrastructure (electricity, internet, hydroelectric dams) or specifically against the weapons program (both conventional and nuclear). While the U.S. has the best suite of offensive cyber tools globally, this is still a difficult option to execute. An interesting aspect of using cyber tools is that they could be used selectively in a way that leaves both the North Koreans and their potential partners and arms customers unsure of the quality and reliability of their systems -- without fully expending all of the U.S. offensive cyber options.