In North Korea, a dozen U.S. arms experts began their second annual inspection of a mysterious tunnel complex. In Moscow, Deputy Secretary of State Strobe Talbott haggled with Russian officials over amending a 28-year-old arms agreement. In Washington, Republican presidential hopeful George W. Bush made a strong pitch for a still unproven global missile defense system. And addressing graduates at the U.S. Military Academy, Vice President Gore called for a more limited missile defense.

The common goal of these disparate events last week? Stopping a "rogue" state--irrational, reckless and armed with nuclear missiles capable of striking American shores.

The existence of such a threat has become an article of faith, widely accepted by the Clinton administration and some of its Republican critics, but questioned by some policy experts here and by many abroad. Many U.S. policymakers warn that a rogue state--whether an isolated and paranoid North Korea, a religiously motivated Iran or a vengeful Iraq--might attack the United States even if the inevitable result would be retaliation so massive that the attacking state would be obliterated.

"There are new threats in the world," said Samuel R. "Sandy" Berger, President Clinton's national security adviser. "One of those is the growing capability of North Korea and Iran, who may not be as susceptible to deterrence as the Soviet Union was."

When President Clinton visits Moscow next week for his first summit meeting with Russian President Vladimir Putin, rogue states will be the ghosts at the negotiating table. Fear of their still-theoretical capabilities has made winning Russia's agreement for a limited American missile defense the Clinton administration's top priority in Russia policy, overshadowing the war in Chechnya, economic reform and future NATO expansion.

Yet some policy experts question the assumption that there are such irrational rogues.

"The unexamined assumptions about this are extraordinary, and the biggest is the presumption that a variety of misbegotten states are not subject to the same constraints of nuclear deterrence that everybody else has been subject to," said Jonathan Pollack, an Asia specialist at the Rand Corp., a consulting firm.

Robert S. Litwak, a former director for nonproliferation policy at the National Security Council, argues in a recent book that the rogue epithet "demonizes a disparate group of states" and "significantly distorts policymaking."

There is ample evidence that North Korea, Iran and Iraq have sought, and may still be seeking, weapons of mass destruction and long-range missile technology. North Korea unexpectedly fired a missile over Japan in 1998, and U.N. inspectors discovered massive stockpiles of chemical and biological weapons in Iraq after the Persian Gulf War.

But critics of the theory of rogue states say the allegation that these countries are irrational or suicidal is more questionable. Their leaders appear to be very concerned about self-preservation, and the United States has successfully employed diplomatic as well as military initiatives to engage or contain them.

Nearly a decade after the end of the Gulf War, Iraq remains bottled up by sanctions and a steady U.S.-British bombing campaign. In the wake of electoral victories by moderates in Iran, the Clinton administration has made some conciliatory gestures to Tehran while still seeking to block technology transfers.

North Korea, meanwhile, has largely complied with a 1994 agreement aimed at making sure its nuclear program is peaceful. Within the past two months, workers under the supervision of an Atlanta-based company finished putting spent fuel from a North Korean nuclear reactor into sealed canisters, bringing to roughly 8,000 the number of radioactive rods sitting under lock, key and camera in a murky pool. Only about a dozen fuel rods are missing, a U.S. official said, far short of the amount needed to build a nuclear bomb. Last week, North Korea also fulfilled a commitment to let U.S. inspectors return to the mysterious tunnel complex once suspected of concealing a nuclear weapons or missile program. And it is preparing to hold its first summit with South Korea, its longtime foe.

"You speak about North Korea as an irrational country when you have been negotiating with North Korea for six years," said a European diplomat. "The 1994 agreement was a rational agreement."

French Foreign Minister Hubert Vedrine noted that there is no translation for rogue state in French. "It's not a geopolitical category we use," he said. "It is difficult for Europeans to imagine one of these rogue states attacking the United States."

Noting that U.S. officials could just as easily call Libya, Pakistan or India rogue states, and that the United States appropriately pursues different policies toward different so-called rogues, Vedrine suggested the label was simply a rhetorical tool.

Dmitri Rogozin, chairman of the international relations committee in the Russian Duma, said the United States was exaggerating the North Korean threat. "A cannon is not the best weapon to shoot at flies," he said.

Moreover, Rogozin predicted that the United States would react strongly if it detected North Korean preparations to fire a missile. "I highly respect the U.S. military, and I can't imagine that the U.S. military would sit idly by and watch the threat from North Korea," the Russian parliamentarian said. "They will simply smash this country."

A U.S. official who has been deeply involved in negotiations with impoverished North Korea said that despite its philosophy of self-reliance, Pyongyang has always relied on outside assistance. Now that its former patron, the Soviet Union, is defunct, North Korea is clumsily seeking a new sponsor.

"North Korea is one of the few totally parasitic countries," the official said. "It has lost its host. But parasites don't commit suicide."

He added, "They are not going to nuke Hawaii because they realize they will be annihilated. People who say we need national missile defense because North Korea is crazy are only those who don't know anything about North Korea. North Korea is mainly a threat to itself."

Yet fear of rogue states remains widespread. The term "rogue" originally was applied about 20 years ago to countries whose internal policies were oppressive. (It was once applied by the Wall Street Journal to Ohio for its environmental policies.) Beginning in the mid-1990s, the term was attached to countries that might act irrationally in the international arena.

In a Foreign Affairs article in early 1994, then-Clinton national security adviser Anthony Lake called for "confronting backlash states" that were characterized by "chronic inability to engage constructively with the outside world." In April 1996, then-Secretary of Defense William J. Perry warned of a "future threat that a rogue state, that may be impossible to deter, will obtain ICBMs that can reach the United States." In September 1997, Secretary of State Madeleine K. Albright said that "dealing with the rogue states is one of the great challenges of our time . . . because they are there with the sole purpose of destroying the system."

A commission headed by former defense secretary Donald Rumsfeld enshrined the rogue threat as official doctrine. When the commission released its report in 1998, it declared that "concerted efforts by a number of overtly or potentially hostile nations to acquire ballistic missiles with biological or nuclear payloads pose a growing threat to the United States, its deployed forces and its friends and allies." The report added that those states "would be able to inflict major destruction on the U.S. within about five years of a decision to acquire such capability."

That put time pressure on the Clinton administration. And so with the Cold War over, deep cuts in the nuclear arsenals of the superpowers, American military might unparalleled and the nation at peace, both Democrats and Republicans have been edging closer toward a decision to build one of the most expensive weapon systems in history.

To be sure, some people worried about rogue states nonetheless oppose the current national missile defense proposal. Richard Garwin, a member of the Rumsfeld commission, argues that it would be easier to put a lid over a handful of rogues than to put an umbrella over the entire United States. He favors a modest missile defense known as boost phase, which would be based close to rogue state borders and intercept missiles on their way up. Other experts warn that rogue states could deliver weapons of mass destruction in boats, suitcases, cars or vials instead of intercontinental missiles.

Still other policymakers warn of letting concern about small rogue states prompt the shredding of major accords, like the 1972 Anti-Ballistic Missile Treaty that the administration is trying to persuade Russia to amend.

But national missile defense remains an alluring prospect for those worried about preserving America's latitude for action in a crisis, when a small country with nuclear missiles might threaten to use them.

"Deterrence is probably good enough," former Clinton national security adviser Lake said in an interview. "But when the stakes are so high, I'm not sure that 'probably' is good enough."

Bush adviser Condoleezza Rice said the United States should press ahead with national missile defense even if it means the end of the ABM Treaty. "The ABM Treaty is an artifact of a different period of time," she said. "ABM was designed to prevent national missile defense. It is not clear to me how, with minor changes, you get around that. It's a new world."