Winning an insanity defense an uphill battle

Aaron Schaffhausen has pleaded guilty to killing his three young daughters at the family's River Falls, Wis. home, but has maintained that he shouldn't be held responsible because he was insane at the time. Presecutors have argued Schaffhausen was perfectly aware of what he did.

An insanity defenses is a tough sell to a jury, according to a report by Steve Karnowski of the Associated Press.

"Winning with an insanity defense is usually an uphill battle, though the legal test in Wisconsin is somewhat easier than in other states," Karnowski writes. "Wisconsin requires at least 10 of the 12 jurors to find the evidence shows a defendant suffered from a 'mental disease or defect' so great at the time that he or she 'lacked substantial capacity either to appreciate the wrongfulness of his or her conduct or conform his or her conduct to the requirements of law.'"

Former Ramsey County Attorney Susan Gaertner joins The Daily Circuit to discuss how insanity pleas work.

LEARN MORE ABOUT INSANITY PLEAS:

• Good Question: How Does An Insanity Defense Work? WCCO's look at the ins and outs of insanity pleas.

• Not Sick Enough: The Insanity Defense. Part of the American RadioWorks documentary "Jailing the Mentally Ill."

• A crime of insanity. PBS' Frontline looks at the case of a person with paranoid schizophrenia on trial for a violent crime.