"They serve with valor. They serve with distinction, and when they're at their home base, they need to feel safe," Obama said Wednesday. "We don't yet know what happened tonight, but obviously that sense of safety has been broken once again."
Army psychiatrist Nidal Hasan was convicted last year for the November 2009 mass shooting at Fort Hood. According to trial testimony, he walked into a crowded building, shouted "Allahu Akbar!" — Arabic for "God is great!" — and opened fire. The rampage ended when Hasan was shot in the back by base police officers.
Hasan, now paralyzed from the waist down, is on death row at the military prison at Fort Leavenworth in Kansas. He has said he acted to protect Islamic insurgents abroad from American aggression.
After that shooting, the military tightened base security nationwide. That included issuing security personnel long-barreled weapons, adding an insider-attack scenario to their training, and strengthening ties to local law enforcement. The military also joined an FBI intelligence-sharing program aimed at identifying terror threats.
In September, a former Navy man opened fire at the Washington Navy Yard, leaving 13 people dead, including the gunman. After that shooting, Defense Secretary Chuck Hagel ordered the Pentagon to review security at all U.S. defense installations worldwide and examine the granting of security clearances that allow access to them.
Asked Wednesday about security improvements in the wake of the shootings, Hagel said: "Obviously when we have these kinds of tragedies on our bases, something's not working."