Obama denies crotch bomber conspiracy

Not quite. The Christmas Day attack demonstrated the adaptive and organized nature of the terrorist threat. Al Qaeda chose a flight originating overseas to avoid U.S. domestic security measures. Nigerian bomber Umar Farouk Abdulmutallab reportedly boarded the aircraft by impersonating a Sudanese refugee who did not have a passport, a ruse officials in Amsterdam apparently accepted. It is certain that al Qaeda had tested this method at Amsterdam before.

The PETN explosive was hidden in Mr. Abdulmutallab's underwear to avoid detection. The reagent that he used to set off the PETN reportedly was brought onboard in a syringe, which not only would be useful for introducing the reagent to the explosive but facilitated smuggling it, for example under the guise of it being insulin. The only part of the terrorist plan that failed was the bomb itself, which either was not prepared correctly, was damaged in transit or was not detonated properly. However, even the malfunctioning bomb produced a fire that could have brought the aircraft down had it not been extinguished quickly.

This attack demonstrates al Qaeda's sophistication and adaptation. The tactic Mr. Abdulmutallab used to bring the explosive onto Flight 253 will be particularly difficult to thwart. Shoe-bomber Richard Reid's failed attack forced air travelers to grow accustomed to removing footwear in airports; the impact of the "crotch bomb" on airline passengers can only be imagined.

Once that's in place, killers could just move on to concealing bombs in more difficult-to-search places. In fact, they already have. In August, high-profile terror suspect Abdullah Asieri wounded Prince Mohammed Bin Nayef, Saudi Arabia's counterterrorism chief, after smuggling a pound of high explosives and a detonator into an interrogation room in his rectum.

President Obama referred to Mr. Abdulmutallab as an "isolated extremist," and Ms. Napolitano said there was "no indication" that the attack was "part of anything larger," which seems to be the Obama administration's default setting when faced with terrorism. They said as much about the Nov. 5 Fort Hood massacre, even though the FBI had previously monitored communications between shooter Nidal Malik Hasan and Anwar al-Awlaki, the radical imam and al Qaeda commander born in New Mexico and believed to be in Yemen.

Mr. Abdulmutallab also reportedly is one of Mr. al-Awlaki's followers and said he was one of many bombers trained in Yemen who will seek to attack the United States. Other evidence pointing to a larger plot includes a report that Mr. Abdulmutallab had an accomplice in Amsterdam, the sophistication of the bomb design, and al Qaeda's admission that it was behind the attempt. Note also that Mr. Abdulmutallab was placed on a terrorist watch list after his father reported to U.S. authorities in Nigeria that his son had fallen in with a group of dangerous radicals.

The impulse to deny that attacks such as the Christmas Day bombing and Fort Hood massacre are part of larger plots displays a shocking ignorance of the nature of 21st-century globally networked terrorism. Terrorists work through highly dispersed, decentralized cell structures that are designed to be difficult to track. Investigators probably won't find an operations order signed by Osama bin Laden directing an attack on Flight 253, but it is easy to connect the dots. Minimizing the threat won't make it go away. As recent history has shown, it may embolden the terrorists to keep trying.