The North Korea atomic weapons crisis has come to a head. Understanding this situation is a whole lot easier than many think. Like a boil, it must be lanced.

North Korea now has the four elements needed to present a credible nuclear missile threat to the United States and many other nations: a big-enough rocket, a nuclear warhead small enough to ride that rocket, a guidance system to get it near its target and a heat shield for the warhead to survive blistering reentry.

Its recent high-arcing rocket tests demonstrate North Korea has made sufficient progress on all four fronts. The trajectory shows the capability of hitting the United States if aimed differently; intelligence communities agree it has a bomb small enough to ride that particular rocket; and, finally, the fact these test flights have not gone astray shows the guidance system works. And the evidence strongly suggests the heat shield works.

Whether this intercontinental ballistic missile system is actually reliable is beside the point, same as it was with ours and Russia’s back in the 1950s. If they launched several, at least a few were sure to hit the target. Now that he has a credible weapon, North Korean ruler Kim Jong Un is ready to play the age-old blackmail game.

The game is played thusly: The aggressive one makes a threat to do something “unspeakable” unless he gets what he wants. He must be willing to risk getting slapped down for it but, throughout history, most of those who are willing take that risk.

Between world wars the “unspeakable” threat was to wage war at all, particularly after the horrifying experiences of World War I. Since World War II, the unspeakable threat has been to wage nuclear war. Notice how lots of conventional wars have been waged since then. Only the technology deemed “unspeakable” has changed. The game remains the same.

Kim Jong Un may seem crazy, but he’s crazy like a fox. It’s not yet clear what he wants, but he has already made the threat to nuke Guam, a U.S. territory in the Pacific. His risk bet is we won’t go to war over an island far from our shores. That’s why he has not yet threatened the lower 48 states. But as this escalates, Hawaii and Alaska are at risk because of U.S. military assets in both places, plus our allies in the region.

And escalate it will, just as with Hitler and the Nazis in 1930s Europe. This scenario has played out countless times over history. Kim Jong Un is following a long-established pattern.

Of course, there’s no excuse not to pursue a diplomatic solution. Basic humanity on our part demands it. But don’t hold your breath for it to work. It didn’t work with Hitler or his ilk. What worked was raw force. The only question is how much you have to use.

This is very much like a boil: The longer it festers, the more it hurts when you finally lance it and the more damage there is to heal afterward.

It’s important that we not strike the first blow. That’s true even without any pronouncements from the Chinese as to whether they get involved. It’s also important we not resort to half-measures such as only striking test sites. This is the main lesson of World War II: Go “whole hog” or none. If North Korea strikes Guam or anywhere else, we take out Kim Jong Un and his entire government. Regime change or nothing. Period.

It would be nice if we could kill Kim and all his government functionaries by destroying them in their big-government complex in Pyongyang without killing the pitiful civilians in the surrounding city. Then there’s no need to send one tank or one soldier across the border or to commit genocide by nuking the entire city. The size of this dictator’s bunker-complex demands we use a deep-penetrating “bunker-buster” projectile fitted with a small nuclear warhead, exploded deep underground, turning the complex into a contained rubble pile in a pit too radioactive to enter. For the most part, the city and people survive. Only Kim Jong Un and his government perish.

Yet I haven’t heard we actually have such a weapon. North Korea has been festering since 1953, so it’s not like we haven’t seen this problem coming for many moons now. One wonders if we’ve spent too much time over too many years developing the wrong kind of weapons. Think about this next time you vote — which, of course, will be way too late to do anything about all of this.

Meanwhile, sleep tight!

Gary W. Johnson is a former cutting-edge aerospace defense engineer and lives in McGregor, not far from SpaceX’s rocket-testing facilities.