During his first week as commander in chief, President Barack Obama ordered the closure of Guantanamo Bay and terminated the CIA's special authority to interrogate terrorists.

While these actions will certainly please his base -- gone are the cries of an "imperial presidency" -- they will also seriously handicap our intelligence agencies from preventing future terrorist attacks. In issuing these executive orders, Mr. Obama is returning America to the failed law enforcement approach to fighting terrorism that prevailed before Sept. 11, 2001. He's also drying up the most valuable sources of intelligence on al Qaeda, which, according to CIA Director Michael Hayden, has come largely out of the tough interrogation of high-level operatives during the early years of the war.

The question Mr. Obama should have asked right after the inaugural parade was: What will happen after we capture the next Khalid Sheikh Mohammed or Abu Zubaydah? Instead, he took action without a meeting of his full national security staff, and without a legal review of all the policy options available to meet the threats facing our country.

What such a review would have made clear is that the civilian law-enforcement system cannot prevent terrorist attacks. What is needed are the tools to gain vital intelligence, which is why, under President George W. Bush, the CIA could hold and interrogate high-value al Qaeda leaders. On the advice of his intelligence advisers, the president could have authorized coercive interrogation methods like those used by Israel and Great Britain in their antiterrorism campaigns. (He could even authorize waterboarding, which he did three times in the years after 9/11.)

Mr. Obama has also ordered that all military commission trials be stayed and that the case of Ali Saleh al-Marri, the only al Qaeda operative now held on U.S. soil, be reviewed. This seems a prelude to closing the military commissions down entirely and transferring the detainees' cases to U.S. civilian courts for prosecution under ordinary criminal law. Military commission trials have been used in most American wars, and their rules and procedures are designed around the need to protect intelligence sources and methods from revelation in open court.