North Korea's thermonuclear warhead solves one of the biggest problems with its missiles
North Korea has demonstrated missiles that can range the continental US from its various launch sites, but range represents just a small part of the equation.
Not only does an intercontinental ballistic missile need to have tremendous power to give it range, it needs high-tech composite materials to help it survive reentry into the earth's atmosphere.
Serious questions remain about North Korea's ability to build a reentry vehicle that can survive the insane pressure and heat associated with diving through earth's atmosphere at many times the speed of sound.
Mike Elleman, senior fellow for missile defense at the International Institute for Strategic Studies, previously told Business Insider that the first time North Korea launched an ICBM, the reentry vehicle failed catastrophically in the last few seconds before impact.
North Korea may have since corrected this issue, but it still needs to test its missiles at long range, instead of firing them straight up and down. Tests on a regular trajectory can give them good data about reentry vehicle survival, but even if it works, they have to figure out how to guide the missile.
The US has fielded nuclear ICBMs since 1961, but it continues to work on accuracy. The US may spend about $400 billion on upgrading its ground-based Minuteman III missiles in large part to increase their precision within the coming years.
North Korea, fledgling when it comes to ICBMs, has nowhere near the accuracy with missile fires that the US has. As the North Korean ICBMs have not been tested at range, nobody, including Kim Jong Un, knows how accurate the missiles would be.
But having a gigantic explosive at the end of the warhead fixes that. If a warhead can explode with the force of hundreds of kilotons of TNT, it doesn't really need to be accurate. North Korea could miss San Francisco by miles and still kill hundreds of thousands along California's densely populated coast.
North Korea breaking through to hydrogen bombs, as opposed to atom bombs, means its missile program has become exponentially more effective, and a much greater threat to the US.