The suspects detained by the Justice Department after Sept. 11 are dangerous. So dangerous that they may have to be tried in secret military tribunals, where they can’t see the evidence against them and where a two-thirds vote is good enough for the death penalty. So dangerous, in fact, that the government can’t even tell you their names.

But not too dangerous to buy guns.

Since Sept. 11, the FBI has tried twice to determine whether anyone detained in connection with terrorist activities bought guns shortly before their arrest. Members of al-Qaeda could still be operating in the United States and could still be planning terrorist attacks, and the FBI wanted to find out what kind of firepower they had. The federal government keeps records of gun purchases for 90 days after the background check, and a limited search found that at least two detainees had recently bought guns. But John Ashcroft’s Justice Department has forbidden the FBI from examining the rest of the records and is now trying to have them all destroyed.

Ashcroft, who graced the cover of a National Rifle Association magazine this summer, has long opposed using these records for law enforcement purposes out of the fear that it will lead to a national gun registry. He has repeatedly claimed that retaining the records is illegal, even after the Supreme Court has ruled otherwise. As a senator in 1998, Ashcroft tried to amend the law, but his amendment was defeated. Now the attorney general is seeking to change the law on his own by refusing to enforce it, preventing the FBI from accessing the information and attempting to have all the records destroyed 24 hours after the background check is completed.

The federal government normally keeps the records from recent background checks for 90 days, for (among other purposes) “investigating, prosecuting, and/or enforcing violations of criminal or civil law.” There could be no more appropriate use of the records than to investigate and prevent acts of terrorism. Even if Ashcroft were right and if current law prevented the FBI from using the records, that law can be changed. The Justice Department has repeatedly asked Congress for more flexibility in wiretapping and other matters, and there’s no reason to leave gun purchases out.

The International Association of Chiefs of Police has written two letters asking Ashcroft to release the records to the FBI, but the attorney general has turned a deaf ear to their pleas and to those of senior FBI officials. For a man who has been so dismissive of fundamental liberties and of the right to privacy in all other walks of life, Ashcroft seems determined to protect the privacy of gun owners—even if they’re members of al-Qaeda. In the words he used before the Senate Judiciary Committee, Ashcroft’s decision may not give pause to America’s friends, but it quite literally “gives ammunition to America’s enemies.”

The attorney general’s job is to protect public safety, not the gun lobby. Ashcroft should have told his friends in the NRA what he told the Senate: “To those who scare peace-loving people with phantoms of lost liberty, my message is this: your tactics only aid terrorists.”