Scotland Yard successfully penetrated the plotters of a mass terrorist attack against airliners bound from the United Kingdom to the United States on Aug. 10 British time, resulting in the capture of nine people who planned to use liquid explosives contained in carry-on luggage to down the planes. Current reports indicate at least 21 people have been arrested in total, and perhaps the cell contains as many as 50 people.

There are four takeaway lessons from this incident:

First, while there obviously remains a threat from those not only sympathetic to al Qaeda, but actually participating in planning with those in the al Qaeda apex leadership, their ability to launch successful attacks outside of the Middle East is severely degraded.

Second, if the cell truly does have 50 people and 21 have already been detained, then al Qaeda might have lost its ability to operate below the radar of Western -- or at least U.K. -- intelligence agencies. Al Qaeda's defining characteristic has always been its ability to maintain operational security. If that has been compromised, then al Qaeda's importance as a force has diminished greatly.

Third, though further attacks could occur, it appears al Qaeda has lost the ability to alter the political decision-making of its targets. The Sept. 11 attack changed the world. The Madrid train attacks changed a government. This failed airliner attack only succeeded in closing an airport temporarily.

Fourth, the vanguard of militant Islam appears to have passed from Sunni/Wahhabi al Qaeda to Shiite Iran and Hezbollah. It is Iran that is shaping Western policies on the Middle East, and Hezbollah who is directly engaged with Israel. Al Qaeda, in contrast, appears unable to do significantly more than issue snazzy videos.

This shift will obviously refocus Western -- and particularly U.S. -- foreign policy from the old threat to the new threat.

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