North Korea is today the greatest danger we have ever faced as a nation. Its rapidly growing nuclear arms capabilities represent a literally existential danger of a kind which could sow unimaginable death and destruction and spell doom for American civilization. If we do not act now, we heedlessly risk the deaths of tens of millions of Americans by putting the fate of the United States in the hands of a madman.

Events are moving rapidly, and the window of opportunity for effective self-defensive action is closing. Last week the Pentagon’s Defense Intelligence Agency announced that within a year North Korea will have a viable nuclear capable intercontinental ballistic missile. And then just days later North Korea successfully test-launched its first ICBM, one capable of hitting the west coast of the United States. Once it overcomes the last technological hurdle, designing a nuclear warhead able to survive re-entry from flight, the regime in Pyongyang will be on the cusp of becoming a nuclear super-power. Then, the final and relatively easy step will be mass production of nuclear-tipped missiles.

We went to war against Japan and Germany because they aspired to hegemony over Asia and Europe. We fought in Korea and Vietnam to prevent forced reunification of those countries under communist domination (unsuccessfully in the latter case). And we invaded Iraq on the unproven but not unreasonable suspicion that Saddam had chemical weapons. These wars were fought to serve important American national interests, but they were not fought to protect the American homeland from imminent danger.

We overthrew the Taliban regime in Afghanistan (at least temporarily) to deny Al-Qaeda a refuge and base of operations after its murderous attack of September 11, 2001. In those attacks, 2996 Americans died. It was the greatest single loss of American civilian lives in our history, and I vividly remember the sense of grief and shock felt by almost all of our countrymen. But in a full nuclear attack launched from North Korea, tens of millions of Americans will die, that is on the order of ten thousand times the death toll of 9/11. And American civilization itself may well collapse under the rubble. One can debate the wisdom and justification of our various wars, but unlike those previous conflicts, destroying North Korea’s ability to wage nuclear war is a matter of national survival.

And once North Korea attains nuclear super-power status, a devastating nuclear war waged on American soil becomes a probability, over a sufficiently long enough period of time. I doubt Kim Jong Un consciously wants to attack the United States, as he is aware the inevitable consequence would be an overwhelming counter-attack and the utter destruction of his regime. But Kim is reckless, brash, and extremely aggressive. And he is a psychopath. It takes only a cursory familiarity with the history of his family’s regime to realize that while he appreciates $10,000 a bottle French Cognac, he has no appreciation for the value of human life.

Kim is dangerous, and once in possession of a massive arsenal of nuclear capable ICBMs he will be a mortal threat to the United States. He will not be able to resist the temptation to use his nuclear arsenal as an instrument of blackmail against the United States and our allies. He will at some point demand reunification of Korea under his personal domination, the abrogation of American alliances in East Asia, and massive financial “reparations” from America. And the risk is that in his bluffing and nuclear gamesmanship, he will miscalculate, with war as an unintended consequence. And Kim is a megalomaniac. In the event of war, he would feel his place in history justified by the destruction of his life-long nemesis, even at the cost of his own life.

Years of American and international sanctions have been laughably ineffective. And it is a fool’s errand to think China can solve this problem for us. China is a strategic trade partner for the U.S. but a strategic military adversary. And while a large-scale nuclear attack on America would cripple China’s economy, it would leave the People’s Republic as the undisputed global hegemon. A nuclear North Korea is less a risk for Beijing than a potential opportunity.

Bill Clinton, George W. Bush, Barak Obama and Donald Trump have all hoped, in vain, that somehow diplomacy could forestall Pyongyang’s steady and relentless march to nuclear super-power status. For decades, the fear that North Korea’s massive artillery batteries just north of the DMZ could rain destruction down on Seoul was an effective deterrent. And yes, in a pre-emptive strike against Kim’s regime, there would be substantial civilian and military casualties, most probably in the tens of thousands. And there would be a diplomatic crisis with an outraged Beijing and an expensive financial burden integrating North Korea with the South.

But the war would be over quickly, in a matter of days. The American military is still the most powerful fighting force in the world, without peers. And yes, the costs in blood and treasure would be immense, unlike any borne by the United States or our allies in decades. But if we do not act, and act soon, the potential (and I think probable) consequences will be unlike anything we as a people have ever endured. And the moment Kim has his first nuclear ICBM, our current overwhelming military superiority turns to helpless impotence. If we fail to destroy this imminent threat while we still have the chance, we unduly risk our survival as a nation.