The U.S. Army psychiatrist charged in the deadly 2009 shooting at the Fort Hood military base in Texas has been arraigned in a military court.

Major Nidal Hasan did not enter a plea during his arraignment hearing Wednesday before a judge at Fort Hood. The judge set a March trial date.

The arraignment came shortly after Hasan's lead attorney, Jim Galligan, decided to step down from the case.

Galligan said he is taking a temporary leave of absence, but he declined to explain why. He said he is willing at some point to resume an “active role” in the case.

Hasan faces 13 counts of premeditated murder for those killed in the November 2009 attack. He also is charged with 32 counts of attempted premeditated murder for the 32 people wounded in the shooting.

Fort Hood's commander has said Hasan faces the death penalty.

U.S. officials have linked Hasan to a radical Muslim cleric in Yemen. Witnesses say he shouted “God is great” in Arabic just before opening fire.

The incident has raised concerns about the threat of “homegrown” terrorist attacks.

Hasan was paralyzed from the waist down after being shot by police on the day of the rampage, and he remains in jail.

A U.S. Senate report released earlier this year said federal authorities could have prevented the Fort Hood massacre. An investigation found that although the U.S. Defense Department and Federal Bureau of Investigation did not have specific details about the attack, they collectively had enough information on Hasan to detect his radicalization to violent Islamic extremism.

The report said authorities knew that Hasan had contacts with a “suspected terrorist,” and it pointed out that an instructor and colleague referred to him as a “ticking time bomb.” But the report said the Defense Department and the FBI failed to understand or act on what they knew.