Overnight, North Korea was shaken by a 6.3 earthquake in what that country claimed to be the first test of a Hydrogen Bomb small enough to be mounted on an ICBM. The test was quickly condemned by various interested powers, including the United States, South Korea, Japan, and China. However, the nuclear test, coupled with a recent missile test, suggests that measures to curb North Korea diplomatically and economically are not working.

What a North Korean hydrogen bomb would mean

A hydrogen bomb, as opposed to the atomic weapons that North Korea has previously tested, would have a yield in the hundreds of kilotons, as opposed to a few tens of kilotons.

Couple such a weapon with a working ICBM and North Korea would be able to place the entire United States at risk. An air burst from an H bomb would devastate potentially hundreds of square miles of territory, rendering it uninhabitable for decades. An explosion from such a weapon would take millions of lives in an eye blink and much more from the lingering effects of radiation sickness and burns.

What kind of options does the United States have now?

With diplomatic and economic options running out, the United States will likely have to take sterner measures. Reliance on mutually assured destruction to deter North Korea is not an option. MAD depends on an enemy with a modicum of sanity to work.

It is clear that Kim Jong-un is not sane and is heedless of the consequences of nuclear brinkmanship. He is capable of launching a nuclear strike without taking into account a response that would destroy his country, his people, and him personally.

One no brainer for the United States and its allies will be to augment its missile defenses as rapidly as possible.

Defense against ballistic missiles was neglected under President Obama. President Trump will have a lot of catching up to do, ringing North Korea with existing missile defense systems and creating new ones.

Beyond that, a number of risky military options exist. We could try to assassinate Kim and his inner circle, the theory being that anyone who replaces him has to be saner and more prone to reason.

We could launch a limited strike on North Korea’s nuclear and missile programs. Or we could mount an all out air campaign to eliminate that country’s capability to make war. Every military option contains the risk of a significant cost in lives and treasure. But North Korea’s persistence in creating weapons of mass destruction is creating a situation in which doing nothing may well cost much more.