Pre-emption used to be the watchword of Bush foreign policy. The world's sole superpower would not hesitate to wield force against an imminent threat to its security. The old doctrines of the Cold War era -- of containment and deterrence of a potential enemy -- were disdained as weakness.

Now, facing the most serious national security challenge since the end of the Cold War -- the nuclear weapons programs of Iran and North Korea -- the administration is reaching back to those oldies but goodies.

The determination of Iran and North Korea to develop nuclear weapons has so far been largely unchecked by this administration. The North Koreans, since breaking out of the freeze agreed to during the Clinton administration, have been steadily producing plutonium, and presumably warheads. The Iranians, after the election of hard-line President Mahmoud Ahmadinejad, reversed their deal to suspend uranium-enrichment activities, the crucial step toward nuclear weapons.

Diplomatic negotiations in both cases have produced little movement. But a military strike on their nuclear facilities is almost inconceivable. The danger of potentially horrendous retaliation and the sapping of American will and resources in Iraq have almost killed that option.

"As shaky as a policy of containment is, it is certainly preferable to confrontation, 'rollback,' or 'regime change' through military force,'' wrote conservative national security expert Thomas Donnelly in a recent analysis. "Containment is, in fact, regime change by tolerable means, and the solution to the problems of Iran and North Korea lie in an indirect approach.''

While we try to contain a nuclear Iran and North Korea, suggested Donnelly, we should surround Iran with movements for democratic change in Iraq and Afghanistan. North Korea, he believes, will be changed through Chinese influence.

Donnelly cautions that there may be circumstances when containment proves even more risky than intervention -- say if Iran tries to slip nuclear materials to Islamist terrorists. Iran is less stable than the Soviet Union, though it is worth remembering that the first 15 years of the Cold War brought us to the brink of nuclear war once and close to it several times.

For the administration, this is a stealth policy shift. That is no surprise. It flows directly from the mess in Iraq, a mistake the administration can never really acknowledge.

For those who once touted American global domination, it is still hard to face the reality that containment is impossible without allies and partners. By ourselves, we cannot press those regimes by cutting off their access to investment and advanced technology.

The administration is rightly moving to take Iran to the United Nations Security Council to seek a mandate to enforce the demands of the International Atomic Energy Agency. North Korea is undoubtedly watching this carefully.

China and Russia, who have veto power in the Security Council, are reluctantly going along. But they still resist any move to impose economic sanctions against Iran. Nor are the Europeans, Japanese and others who depend on oil and gas from Iran eager to halt their investment and trade.

Similarly in the case of North Korea, the Chinese and South Koreans are not prepared to cut the flow of economic aid and investment into the otherwise isolated North Korean state. This is less a case of economic interests than a fear that sanctions will escalate to greater confrontation, even war.

"The strategic challenge the Bush administration faced was to convince the rest of the world that Iran is more dangerous than the United States,'' says nuclear proliferation expert George Perkovich. "They finally did it -- and it took Ahmadinejad to do it,'' referring to the inflammatory rhetoric, including threats to "wipe Israel off the map,'' issued by the Iranian leader.

The administration made some headway down the same path with North Korea by engaging in direct talks with that regime this past fall, dispelling the image that the United States was unwilling to negotiate. But that progress has been undermined recently because hard-liners inside the Bush administration pulled the plug on such talks.

Managing an effective containment partnership will be a huge challenge. And there is still tremendous resistance inside the administration to engaging and negotiating -- and compromising -- with the enemy. But that was always a part of making containment succeed, even at the height of the Cold War.

Containment is no silver bullet. It is merely, as Donnelly puts it, "the least bad alternative, but not by a lot, and not under all circumstances.'' And right now, it is the only game in town.