Jared Loughner, accused of shooting Gabrielle Giffords and killing 6 people in a rampage in Tuscon this January, has been ruled mentally incompetent to stand trial by a federal judge today.

The decision by U.S. District Judge Larry Burns means 21-year-old Jared Lee Loughner will be sent to a federal facility for up to four months in a bid to restore his competency.

Wednesday’s ruling comes after Loughner spent five weeks in March and April at a federal facility in Missouri, where he was examined by two court-appointed mental health professionals.

Loughner has pleaded not guilty to the charges that he killed 6 and injured 12 in a shooting spree at a shopping mall January 8. His lawyers haven’t explicitly said they would pursue an insanity defense at trial, but based on previous filings it’s clear that would compose a major part of their defense.

There has been no public release of the competency reports from the mental health experts who worked with Loughner in Missouri, but clearly they found him unfit to stand trial. I’m not sure another four months will change that outlook.

Giffords remains in rehabilitation from her injuries and recently had skull surgery.

Dahlia Lithwick mused about Loughner’s competency and the insanity defense back in January.

Contrary to popular belief, the insanity defense is used in fewer than 1 percent of all cases and only has about a 26 percent success rate. In 90 percent of the successful claims, the defendants had been previously diagnosed with mental illness. According to the American Psychiatric Association, defendants acquitted by reason of insanity are likely to spend as much if not more time incarcerated in a psychiatric institution as they would have had they had gone to prison for the same crime. Some studies say that those found insane spend twice as much time under lock and key as they would have spent in jail—and they remain under supervision long after their criminal counterparts are freed.

I am not going to try to diagnose Jared Lee Loughner from my desk today. My only long-distance observation is to say we should be doing a far better job of diagnosing and caring for those with serious mental illnesses, and of making sure that they can’t get their hands on guns. And to anyone who claims to know today how much of Loughner’s conduct last weekend was rational and how much was pathology, all I ask is this: Please stand by your words if and when Loughner and his experts and lawyers someday opt to make those very same arguments in court.