Less than a year before allegedly slaying 13 people and wounding 30 others at Fort Hood last November, U.S. Army Maj. Nidal Malik Hasan reportedly exchanged as many as 20 e-mails with radical cleric Anwar al-Awlaki in Yemen, asking about jihad and whether it was acceptable to kill American soldiers.

Apparently upsetting Maj. Hasan, a psychiatrist, was his impending deployment to Afghanistan. He was prone to making Islamic extremist remarks to associates and in online postings. In addition, according to published reports, he received poor performance reviews, and required counseling and extra supervision while an intern at the Walter Reed Army Medical Center before his transfer to Fort Hood.

Records suggest that in 2001 he attended the same Islamic mosque in Virginia as two of the September 11 hijackers.

If these reports are true, just how many red flags did Army and intelligence officials miss or ignore before Maj. Hasan allegedly opened fire at Fort Hood's Soldier Readiness Center Nov. 5, 2009, shouting "Allahu Akbar!" ("God is greatest")?

The U.S. Senate's Homeland Security and Governmental Affairs Committee is determined to find out, and last week Sens. Joe Lieberman, D-Connecticut, the committee chairman, and Susan M. Collins, R-Maine, the vice chairwoman, issued subpoenas demanding access to Defense and Justice department records of the Fort Hood investigation.

They say the public's right to know whether the government had any information about Maj. Hasan that might have prevented the massacre, had it been acted on, supersedes the Obama administration's contention that premature release of these records might compromise a criminal investigation, and also would violate separation-of-powers provisions in the Constitution.

We agree with the senators: Turn over the documents.

Without a thorough Senate probe, the administration would in effect be investigating itself and at best run the risk of appearing to oversee a whitewash. At worst the public might never learn who, if anybody, was at fault for any lapses, and the same mistakes could happen again.

The subpoenas seek not only access to any communications among Joint Terrorism Task Force members regarding Maj. Hasan's communications with Mr. al Alwaki, but also to Maj. Hasan's personnel file and performance evaluations. The senators also want to interview witnesses.

Sen. Lieberman points out that potential witnesses have appeared previously without incident at congressional hearings while criminal cases were pending: during a 1995 probe of the Ruby Ridge shootings, a 1999 spy investigation of Wen Ho Lee and a 2001 joint inquiry into the 9/11 attacks.

The Defense Department also has been dragging its heels in response to the Senate investigation, trying to withhold personnel documents on specious, technical grounds. If anything this dodge only serves to contribute to the odor of a cover-up.

Though we agree with Sens. Lieberman and Collins and urge them to press their pursuit of the records, we also implore them to avoid grandstanding. The public does indeed deserve to know if the government bore any responsibility in the Fort Hood tragedy, but it does not need political posturing that would cheapen any findings.