The package bombs may have failed, but al-Qaeda is still a threat

Some have dismissed al-Qaeda's failed attempt to blow up two planes using package bombs as a sign of the terrorists' weakness. If anything, the opposite is true. This was a serious and sophisticated terrorist plot. Al-Qaeda apparently sent test packages to the United States to map the route they took and probe the airline cargo system for vulnerabilities. Operatives then used the information gleaned from those test runs to evade screening systems, breach airline security and get two bombs on board international flights - including commercial flights with hundreds of passengers.

The bombs were so expertly designed that the wiring was virtually undetectable by X-ray. The material used in the devices, PETN, is one of the world's most dangerous explosives - and the bombs contained 10 times the amount of PETN in the famed underwear bomb of Christmas Day 2009. They were rigged with timers made from cellphones that could trigger explosions in mid-flight. Had they blown up while carried on passenger planes or over a major city, the attack could have been catastrophic.

There are several lessons to take from this plot.

First, while our security investments over the past decade have made it harder for terrorists to carry out attacks, we also face a thinking enemy that is constantly adapting to defeat our countermeasures. Consider: After the Sept. 11, 2001, attacks we hardened cockpit doors to prevent hijackings - so the terrorists used shoe bombs to penetrate our defenses. When we began screening for shoe bombs, the terrorists turned to liquid explosives hidden in sports drinks - and in 2006 they nearly succeeded in blowing up seven planes crossing the Atlantic using such devices. When we began limiting the amount of liquids people could take in carry-on luggage, they penetrated our defenses using underwear bombs - and nearly took down a passenger jet outside Detroit in December. When we added security measures to screen for such devices, they adapted yet again, using bombs hidden in cargo holds. And when we institute new cargo screening procedures in response to this latest attempt, our enemies will adapt yet again - adopting still more creative methods to kill innocent people. We are in a constant race to stay ahead of our enemies, and we cannot let up.

Second, while we need to close off the vulnerabilities al-Qaeda exploited with this attack, we must also recognize that there is no way to defend against every avenue of attack. The only way to protect America is to remain on the offense and stop terrorists before they show up at the FedEx office with package bombs in hand. That requires stepped-up offensive operations in Pakistan, Yemen and parts of East Africa - including the escalation of Predator strikes that President Obama has reportedly put in place. It also requires developing a coherent detention policy so that when we capture senior terrorist leaders, we can interrogate them without resorting to torture and uncover their plans before they are carried out.

Third, we must guard against the notion that recent failures describe a badly weakened enemy. Those who suggest that al-Qaeda does not pose a serious threat if this failed attack is the best it can do could have said the same thing in October 2000, when al-Qaeda blew a hole in the side of the USS Cole. The terrorists failed in their goal of sinking the ship and killed "only" 17 people - far fewer than the hundreds killed and thousands injured in the 1998 U.S. embassy bombings in East Africa. At the time, it would have been easy to dismiss the Cole bombing as a sign of weakness. In fact, it, like the 1993 truck bombing at the World Trade Center, was a precursor to far more deadly attacks to come - as we learned on Sept. 11. Al-Qaeda killed nearly 3,000 people that day using nothing more than plane tickets and box cutters - and we learned that our enemies don't need weapons of mass destruction to cause mass destruction.

We dismiss the danger from al-Qaeda at our peril. As we coped with the immediate aftermath of Sept. 11, many of us recognized that the normal instinct of human complacency would always be a challenge and could be the underpinning of our dramatic failure to protect America. The pace of attempted attacks on America has been growing, not diminishing. In fewer than 11 months, terrorists have penetrated our defenses three times: on Christmas Day, in Times Square and now with this most recent plot from Yemen. In the first two cases, disaster was averted only because the bombs malfunctioned; in the third case, the bombs were uncovered only because we got a tip from Saudi intelligence.

Three lucky breaks in less than a year. Next time our luck may run out - and the consequences could be devastating.

James M. Loy, a retired Coast Guard admiral and a senior counselor at the Cohen Group, a consultancy specializing in defense, foreign and government affairs. He was administrator of the Transportation Security Administration from 2002 to 2003 and deputy secretary of homeland security from 2003 to 2005.