After hurling some choice diplomatic words such as "human scum" and "bloodsucker" at State Department Under Secretary John Bolton last week, North Korea finally agreed to discuss its nuclear weapons program next month in Beijing at the Six-Party Talks (U.S., Japan, South Korea, Russia, China and North Korea.)

But on the heels of this promising development came bad news: The Los Angeles Times reported last Monday that Iran now has highly enriched uranium, secret nuclear labs and scientists from Russia, China, Pakistan and (tah dah!) North Korea running around the country working on nuclear and missile projects.

Then came unconfirmed reports that North Korea plans to export its long-range Taepo Dong-2 missile to Iran, letting Tehran strike as far away as London. (It can already reach Israel.)

It is completely plausible that the North Koreans, Pakistanis and Iranians are working together on ballistic missiles and nuclear weapons, with some help from Chinese and Russians scientists. Heck, it's likely.

This cabal of the world's most notorious weapons proliferators has long roots. For instance, the Russians fathered North Korea's nuclear program during the Cold War. In the '90s, Moscow built nuclear reactors for Tehran (and is still probably providing technical assistance). The Chinese begat the Pakistani nuclear weapons program that came into full bloom in 1998. And Pakistan has likely assisted North Korea's and Iran's atomic quests. China may have also given Iran fissile material in 1991.

Pyongyang, for its part, has helped Islamabad and Tehran with their missile programs. North Korea has sold both nations its No-Dong medium-range missiles, which are the basis for Pakistan's nuclear-capable Ghauri and Iran's Shahab ballistic missiles.

Tehran and Pyongyang have also collaborated on nuclear matters. The number of North Korean technicians in Iran is sufficient to warrant an exclusive Caspian Sea resort for their use. Equally alarming, Pakistan has been implicated in nuclear dealings with the terrorist-supporting nations of Libya and Syria.

The apparent willingness of these diverse regimes to share nuclear secrets is alarming. And considering the company they keep, the possibility that these weapons might eventually fall into the hands of other rogue regimes -- or terrorists -- is legitimate cause for insomnia.

Can anything be done short of sending the Marines over the beaches? Fortunately, yes. America should:

• Move ahead on the Bush administration's Proliferation Security Initiative, which includes planning for the land, air and sea interdiction of nuclear contraband, should diplomacy with North Korea (or Iran) not look promising. Cutting off North Korea's export of missiles (and the hard currency flows, which sustain the regime) would squeeze Kim Jong Il and convince him we're deadly serious.
  
  
• Tighten the economic-sanctions noose around Iran for its noncompliance with U.N. nuclear inspections. Get the European Union to put its trade agreement with Iran on the line. And push Japan, France and Britain to curtail high-dollar Iranian energy deals until Tehran forswears a nuclear future. The Iranian economy is already in the doldrums -- making it worse will make the mullahs squirm and the students even more restive.
  
  
• Insist Moscow halt all cooperation with Iran's nuclear program and use its influence to get Tehran to open to full inspections.
  
  
• Demand Pakistan end all support for Iran's and North Korea's programs (and all others); condition aid and the vitality of the Washington-Islamabad relationship on agreement.
  
  
• Get Beijing to curtail its proliferation activities and lean on Islamabad to comply.
  
  
• Educate other countries about the clandestine front companies that smuggle nuclear contraband, and insist they shut them down.
  
  
• Bring North Korea and Iran's brigand-like behavior before the U.N. Security Council, forcing member nations to take a stand on proliferation.

These measures are certainly not a panacea for these nuclear nightmares. The international community must pull together to defeat nuclear proliferation, or there is no telling where it will end. But taking tough steps now could preclude the possibility of a nuclear Iran, North Korea, Libya, Syria -- or worst of all: a nuclear al-Qaeda.