Go ahead. It's okay to laugh at al-Qaida. It's okay to call Umar Farouk Abdulmutallab the Underbomber, or even the Tighty- Whitey Terrorist. It's okay to call his explosive-bearing undergarment the Jihad Jockeys or the Frighty Whities or Fruit of the Boom. It's okay to laugh about the 'wardrobe malfunction' that kept the bomb in his pants from going off in a plane over Detroit, and about the likelihood that even if the underpants bomb had exploded, there would be '72 very disappointed virgins' when the martyr got to heaven. It is probably even okay to put a photo of the terrorist's singed briefs on the cover of the New York Post with the headlines 'GREAT BALLS OF FIRE' and 'Blast Packing Undies are the Real Hot Pants.' This is all okay because, for all the hand-wringing and finger-pointing surrounding the failed Christmas Day attack, the real lesson of the botched bombing is a happy one: If this is the worst al- Qaida can do, we're in good shape. Yes, it's bad that U.S. authorities missed all the red flags and let Abdulmutallab get so close to success. And it would have been really, really bad if he had blown up the plane. But the dismay of the past two weeks misses a larger point: that the nature of the attack shows just how lame al-Qaida really is. Eight years ago, most experts were convinced that the terrorists would have hit us with a dirty bomb by now. Dirty underpants just aren't as menacing. Remember some of these Post headlines in the months after the Sept. 11 attacks? 'Fears Prompt U.S. to Beef Up Nuclear Terror Detection; Sensors Deployed Near D.C., Borders; Delta Force on Standby'; 'U.S. Fears Bin Laden Made Nuclear Strides; Concern Over `Dirty Bomb' Affects Security'; 'Shadow Government Is at Work in Secret; After Attacks, Bush Ordered 100 Officials to Bunkers Away From Capital to Ensure Federal Survival'; 'Terrorist Attacks Imminent, FBI Warns; ... Assaults on U.S. Called Possible in `Next Several Days' '; 'Al-Qaida May Have Crude Chemical, Germ Capabilities.' But instead of WMD, we got BVDs. 'Blowing up an individual plane is terrible, but it's nothing compared to the catastrophic terrorism risk that most of us feared we'd see soon after 9/11,' said Joe Cirincione, an expert on nuclear terrorism who is president of the Ploughshares Fund. 'We figured there would be a huge escalation in the terrorist attacks.' What emerged instead, he added, was 'one crazy 23-year-old kid with plastic explosives _ this is not the kind of sophisticated attack you'd need to do something like a nuclear weapon.' In part, we overestimated (or, in the case of the Bush administration, perhaps exaggerated) the threat from al-Qaida. In part, the post-Sept. 11 efforts to strengthen the borders and disrupt terrorist operations have worked. Whatever the cause, al-Qaida is now less an organization than a bunch of loosely affiliated cells. These cells are capable of inflicting plenty of pain, as a suicide bomber's killing of seven Americans at a CIA base in Afghanistan last month reminded us. But they do not pose an existential threat to the United States. They can put a kid on a plane with plastic explosives in his pants, but they still can't destroy a U.S. city with loose nukes. This isn't a reason to declare victory or to pull back from the fight, but it is cause to be thankful that things aren't as bad as we thought they'd be. Keeping al-Qaida to this level of 'nuisance' terrorism should be the goal. Attacks by small, uncoordinated cells are harder to prevent, but they aren't as devastating. In the war on terrorism, limiting the enemy to his Frighty Whities is about the best we can hope for. Certainly, the Obama administration should patch the holes in aviation security and fix the newly uncovered gaps in intelligence. But it's more important to redirect some of this frenzy over the underwear bomb to where it really matters: keeping nuclear materials away from terrorists. The president has pledged to do this, and he's gathering some 40 heads of state in Washington in April for the Nuclear Security Summit. Their goal should be to secure remaining nuclear material before al-Qaida and al-Qaida-like groups can get to it, and to end the civilian use of highly enriched uranium. If they can do that _ and that's a big 'if' _ al-Qaida really will be nothing more than Fruit-of-the-Loom fanatics. And the joke will be on them. 