In mid—February, President George W. Bush gave a detailed rundown of how Dr. A. Q. Khan, the "father" of Pakistan's nuclear weapons program, had masterminded covert transfers of nuclear technology and know—how to countries such as Iran and Libya.  As if to underscore the harm the Khan proliferation ring had wrought, international inspectors subsequently found traces of weapons—grade uranium, a key building block for nuclear weapons, on Iranian centrifuges.

The worst part of the whole affair: No laws, domestic or international, were broken.  Dr. Khan was pardoned after publicly confessing to his misdeeds.  But President Bush wrapped up his tough talk about Pakistani proliferation on a Pollyannish note, declaring that "President [Pervez] Musharraf has promised to share all the information he learns about the Khan network, and has assured us that his country will never again be a source of proliferation."

The recent pitched battle in Waziristan, reportedly aimed at capturing or killing Osama bin Laden's number two in command, Ayman al—Zawahiri, indicates that Pakistan is willing to alter its old policy of keeping its troops out of the tribally—ruled area. This Pakistani flexibility is most welcome, and may be the result of Bush Administration pressures arising out of the A.Q. Khan affair. However, under no circumstances should the Administration trade this Pakistani cooperation for continued neglect of urgent and vital concerns relating to nuclear proliferation.

Islamabad has never signed on to the Nuclear Non—Proliferation Treaty, and thus has never legally obligated itself to block proliferation from government or the nuclear industry.  The United States and the rest of the international community have had to content themselves with Pakistan's assurances that it is maintaining tight control of dangerous technology.

The kind of hollow assurances, that is, on which President Bush now intends to rely.

Two explanations for Pakistani proliferation spring to mind.  Gen. Musharraf's government may not have full control of the doings of government agencies.  Pakistan's Directorate of Inter—Services Intelligence, for instance, operates as a virtual state—within—a—state, free of real supervision from the nation's political leadership.

Or Islamabad may have deliberately opted to disseminate weapons—related technology, perhaps out of an unseemly desire for illicit revenue, perhaps out of a misguided belief that proliferation within the Islamic world would fortify deterrence vis—a—vis India.  Either way, the Bush administration must not let Islamabad sweep the Khan affair under the rug.

Why?  Because the United States forcibly deposed the Iraqi regime in large part because it judged intolerable the risk that Saddam Hussein's regime would hand off weapons of mass destruction to rogue regimes or terrorists.  Pakistan has been caught red—handed doing what the administration only suspected Iraq of doing.  The United States has meted out regime change to enemies suspected of abetting catastrophic terrorism.  How should it treat friends who commit the same offense?

First, the administration should exploit the public embarrassment Gen. Musharraf's government is now enduring, which hands the United States a diplomatic lever it hasn't enjoyed up to now.

In 2001, after reviewing security precautions at Pakistani nuclear sites, a team of U.S. officials downplayed the external threat.  The inspectors refrained from urging Washington to furnish Islamabad with the panoply of hardware —— alarms, cameras, and whatnot —— that would improve security at Pakistani facilities.  Washington should begin pushing the Pakistanis —— hard —— to adopt these measures now that the internal threat has become abundantly clear.

There's ample precedent for this kind of assistance to a nation struggling to safeguard deadly weaponry and material.  Since the end of the Cold War, the Pentagon has supplied the Russian military with the equipment and training to bolster security at Russian nuclear weapons sites.  That model could be pressed into service in Pakistan.

Second, Washington should prod Islamabad to install special tags on all critical nuclear—related equipment.  Developed during the 1980s to verify compliance with U.S.—Soviet arms agreements, these tags transmit real—time information about the whereabouts of key items — a kind of LoJack for weapons, fissile materials, and manufacturing capabilities.  This would give the international community a check against malfeasance by future Khans.

Third, the United States needs to ramp up its efforts to help Pakistan upgrade its export control laws and procedures, which exempt the entities involved in the Khan affair from governmental oversight.  Washington has funded one visit by Pakistani nuclear experts to the Los Alamos National Laboratory — and that's it.  The Department of Energy budget for 2005 includes $6.5 million to help emerging supplier states buttress their export controls.

Pakistan would be an ideal beneficiary for this aid.

The Khan affair may spur Islamabad to mend its ways with regard to nonproliferation.  The Bush administration should make it clear that accepting help with nuclear security now is the price of American trust — and assistance — in the future.

James Holmes, Ph.D., is a senior research associate at the University of Georgia Center for International Trade and Security, a think tank dedicated to studying nonproliferation export controls, and a former official in the State Department's Office of International Security and Peacekeeping.