RCW: Let's transition into how the Iranian situation relates to the region, starting with a September 2007 Washington Post Op/Ed in which you wrote, "The most likely next conflict will be with Iran, a radical state that America has tried to isolate for almost 30 years and that now threatens to further destabilize the Middle East through its expansionist aims, backing of terrorist proxies such as the Lebanese group Hezbollah and Hamas in Gaza and the West Bank, and far-reaching support for radical Shiite militias in Iraq. As Iran seems to draw closer to acquiring nuclear weapons, almost every U.S. leader -- and would-be president -- has said that it simply won't be permitted to reach that goal."

Since writing that Op/Ed, how has your own your perception of the Middle East situation evolved?

Gen. Clark: Iran essentially decided it needed to pause in the destabilization of Iraq. Step by step it's cut back on its material support for the militias who were destabilizing and targeting the Sunni populations inside Iraq.

On the other hand, it's continued to move forward with its nuclear programs, installing thousands of centrifuges to enrich uranium. It's approaching the time when it will have enough highly enriched uranium to create a nuclear device. Whether their engineering has been adequate enough to turn that nuclear device into a weapon is unknown. Probably not, but we don't know fully what information they may have gleamed from North Korean or Pakistani efforts to share nuclear technology. So it remains uncertain. The situation remains deeply troubling.

We're approaching the point at which absent either some diplomatic breakthrough that curbs their nuclear programs or some other meaningful non-military intervention; that serious, serious study of military options will be taken.