North Korea probably has one or two bombs now and can produce a half dozen more with plutonium from the fuel rods cooling at Yongbyon. The day its nuclear weapons become operational, we enter a new era in the global balance of power. North Korea cannot defeat the great nations in all-out conflict, but unless they are ready to risk nuclear war, they would be compelled to deal very carefully with the North Koreans. Before his death, Kim got away with much more than Iraq did in 1990, when the allied coalition met its conventionally armed force in a bold, no-nonsense fashion.

The Korean crisis of 1994 is a rehearsal for crises to come. Other Third World nations may not be far behind in acquiring weapons of mass destruction. Iran could be next. Sooner or later, such states as Algeria, Iraq, Libya, and Syria will either learn to make nuclear weapons or purchase them on the shadowy arms market.

In the vocabulary of arms control, nonproliferation is being overtaken by counterproliferation. There is considerable opinion that we cannot prevent the spread of nuclear weapons and may as well accept nuclear coexistence, intervening only in cases of unstable states. Assuming that's true, the problem remains. How do we define the "stable" states? How do we ensure they remain stable? More to the point, what do we do when an unstable state approaches nuclear capability?

We can try warnings and dissuasion. To be effective, a warning must be something besides talk. A year ago, President Clinton warned the North Koreans that pursuit of nuclear weapons could mean "the end of their country." Now, deferring to Mr. Carter, the Administration has even dropped its effort to impose limited sanctions. The results aren't in yet from Mr. Carter's foray in dissuasion.

Another option is preemptive military action. Israel established the tradition in June 1981 when it struck and destroyed the Osirak reactor near Baghdad. Iraq, at war with Iran, did not retaliate. Former National Security Advisor Brent Scowcroft believes that unless North Korea submits to international controls, we should bomb its plutonium reprocessing facility before the new fuel rods are transferred there. That, however, would trigger an intense conventional conflict for which no public support or allied consensus has been developed. Preemptive action in Korea is improbable, especially since Mr. Carter went calling.

Once North Korea's bomb is mounted on a No Dong missile, it will hold at risk all of South Korea and most of Japan. North Korea is dwarfed by the economic stature of its neighbors, but when North Korea talks, they will listen. If the United States appears weak or irresolute, the Asians will conclude that they have two choices: accept North Korea's nuclear advantage and accommodate to it, or acquire their own nuclear weapons.

A nuclear-armed North Korea would send political, economic, and strategic shock waves well beyond northeast Asia. McGeorge Bundy, national security counselor in the Kennedy and Johnson administrations, says the challenge is a parallel to the Cuban Missile Crisis of 1962. That's true, but this time, it could be our side that backs down.

We will face essentially the same crisis again and again as other fringe states--first one, then two, then a dozen--acquire the bomb. If we cannot prevent that, the next question is whether, to keep peace with nuclear-armed radical states, we will modify our national interests and policies. Eventually, a conflict of interest with some future Khomeini or Qaddafi seems inevitable.

When that happens, the preferred option will be to deter the adversary by putting his own vital interests at risk. It has been suggested that the radical states are undeterrable. Let us hope that is not so. Otherwise, our options contract toward a choice between appeasement and war with a nuclear-capable enemy.

The defense Counterproliferation Initiative, announced last winter, seeks improved "ability to destroy, seize, or disable" nuclear arsenals and delivery systems. That is helpful, but it is not enough. If the United States does not demonstrate strength, decision, and leadership, we can hardly expect our less powerful allies to stand firm.

We must weigh carefully the consequences of the proliferation of nuclear weapons in the Third World and reach a fundamental decision about what is tolerable to us. That--and not blustery speeches or desperate optimism--will tell us what our course must be.