Iran-North Korea Nuclear Collaboration...

They're still working closely together...

Now it's Pyongyang's turn to be the link in the nuclear daisy chain. Its ties to Syria were exposed by an Israeli airstrike in 2007. As for Iran, its military and R&D links to the North go back more than 20 years, when Iran purchased 100 Scud-B missiles for use in the Iran-Iraq war.

Since then, Iranians have reportedly been present at a succession of North Korean missile tests. North Korea also seems to have off-shored its missile testing to Iran after it declared a "moratorium" on its own tests in the late 1990s.

In a 2008 paper published by the Korea Economic Institute, Dr. Christina Lin of Jane's Information Group noted that "Increased visits to Iran by DPRK [North Korea] nuclear specialists in 2003 reportedly led to a DPRK-Iran agreement for the DPRK to either initiate or accelerate work with Iranians to develop nuclear warheads that could be fitted on the DPRK No-dong missiles that the DPRK and Iran were jointly developing. Thus, despite the 2007 National Intelligence Estimate stating that Iran in 2003 had halted weaponization of its nuclear program, this was the time that Iran outsourced to the DPRK for proxy development of nuclear warheads."

Another noteworthy detail: According to a 2003 report in the L.A. Times, "So many North Koreans are working on nuclear and missile projects in Iran that a resort on the Caspian coast is set aside for their exclusive use."

Now the North seems to be gearing up for yet another test of its long-range Taepodong missile, and it's a safe bet Iranians will again be on the receiving end of the flight data. Nothing prevents them from sharing nuclear-weapons material or data, either, and the thought occurs that the North's second bomb test last week might also have been Iran's first. If so, the only thing between Iran and a bomb is a long-range cargo plane.