The current antics of North Korea and Iran are simply the latest developments in a process that has been unfolding inexorably since the first nuclear bomb was detonated in the New Mexico desert in July 1945. For about four years, the United States was the only nation able to produce such supremely deadly weapons. Then the Soviet Union succeeded in doing so, followed quickly by Britain, France and Israel. Much later India followed suit, and soon thereafter its great rival, Pakistan.

In recent years, a number of medium-sized nations have shown an interest in acquiring such weapons. Quite a few have developed the nuclear technology to generate electric power for their economies, but that, of course, is a very different thing. Acquiring such nuclear capability requires far less skill and investment than constructing nuclear weapons.

But it has been obvious from the start that sooner or later various nations would elect to go that dangerous route unless steps were taken to prevent them. That was the purpose of the Nuclear Non-Proliferation Treaty, which the United States and the other great powers managed to persuade many nations to sign. But the temptation remained, and the long-dreaded moment has at last arrived when the world is confronted with at least two countries -- North Korea and Iran -- that show every sign of intending to "go nuclear," whether the rest of the world likes it or not.

For better or worse, this has occurred when the United States is the world's only superpower, and thus cannot avoid making the necessary decision: Shall they be permitted to do so or not? Diplomatic pressures, involving both carrots and sticks, are of course being used by many nations to try to dissuade them, but if these fail (and this seems all too likely), the only remaining recourse will be to use military force, and the only country that could conceivably do that is the United States.

It is therefore altogether possible that we will soon have to answer the unavoidable question: "Shall we use force against North Korea and Iran, or not?" Every responsible political leader, from George W. Bush to Nancy Pelosi, not to mention the horde of political commentators, owes the country a clear response to that question. For the next two years, the decisive response will be Bush's; thereafter, it will be his successor's. It may be possible to delay a decision up to some uncertain point, but thereafter the question will in effect have answered itself: "No." (For the record, my answer would be "Yes.") If, voluntarily or by the process of delay, "No" is our answer, let us at least be clear what kind of a world we will have opted to live in. North Korea and Iran will have nuclear weapons. (Indeed, North Korea already has a few.) Other nations will assuredly follow, beginning with their neighbors -- Saudi Arabia, Syria, Egypt, Turkey and Jordan in the case of Iran; Japan, Taiwan and perhaps the Philippines, Vietnam and Thailand in that of North Korea. Then the floodgates will open, as every country in Europe, South America and elsewhere that can afford to "go nuclear" will do so.

And then? Well, for one thing, if a nuclear weapon goes off in some American city, against whom shall we retaliate? The world will become a malignant hall of mirrors in which we cannot even tell who is attacking us.

And if our answer is "Yes," and we use force against North Korea and Iran? The diplomatic consequences, in the case of Iran, would be dreadful. And North Korea, in its despotism's dying hour, might manage to evade our countermeasures and drop one of its small hoard of nukes on South Korea or Japan -- a ghastly consequence. But not as ghastly as condemning the world to live forever in the shadow of assured, and anonymous, destruction.

Be glad you are not President Bush.