All the evidence gathered about Jared Loughner, the 22-year-old student charged with carrying out Saturday's Arizona massacre, points to "a man with a mental disorder" — the disturbing half-smile in his mugshot, the incoherent videos posted to YouTube, the reports of unstable and illogical behavior from former classmates. But if Loughner truly is a "raving lunatic," as many suggest, does that mean he'll be able to plead insanity — and escape the death penalty? (Watch a CBS report about Loughnr's mental state)

No. An insanity defense would likely fail: It's entirely possible Loughner will plead insanity, says Andrew Cohen at Politics Daily, but "there are reasons to think it will fail." Such a defense requires lawyers to prove that the accused was unable to appreciate the wrongness of his acts. Given the boastful suicide note Loughner left, it's likely a jury would conclude "he knew very well he was about to commit a wrongful act."
"Jared Loughner's trial: previewing the Tucson Massacre case"

Loughner is probably insane, but it won't matter: "I am willing to bet" that Loughner has "some type of psychotic disorder," says mental health expert Prof. Mark Heyrman, as quoted in the Daily Kos. But 15 percent of incarcerated felons have "serious mental illnesses," and most didn't plead insanity because it almost never convinces juries. And the government tightened the defense after Reagan attacker John Hinckley used it to escape the death penalty, so it would be a real longshot for Loughner.
"Jared Loughner, mental health and the law"

If you call him insane, then stand by your words: Those who want to label these killings apolitical are quick to blame them on the alleged gunman's "obvious" mental illness, says Dahlia Lithwick in Slate. But I wonder how many of those amateur psychologists who have diagnosed him from afar will have the courage to "stand by [their] words" if Loughner's lawyers "make those very same arguments in court." If a man "is neither culpable nor rational, then it follows that he should not be convicted for his actions," right?
"The insanity defense"