John Hinkley tried to assassinate President Ronald Reagan in 1981 to impress his crush, actress Jodie Foster.
Steve Wasserman allegedly attacked his ex-girlfriend with a 2-foot long medieval-type sword in South Lake Tahoe last month.
Both defendants pleaded not guilty by reason of insanity, a plea that those in legal circles describe as uncommon and tough to defend.
Hinkley was found not guilty. Wasserman, whose charges include attempted murder and mayhem, is now beginning the legal process. His preliminary hearing is scheduled for Wednesday at 1:30 p.m. in El Dorado County Superior Court.
Wasserman also pleaded not guilty to the charges. According to California law, a jury would have to find Wasserman guilty of the crimes before hearing arguments from both the prosecution and defense on whether Wasserman was insane when the crimes were committed.
"If you just do a 'not guilty by reason of insanity,' you basically admit that you did the crime and then the only issue is whether you were insane at the time of the crime," said Wasserman's attorney, Lori London.
Prosecutor Tony Sears said he'll be working the criminal aspect and attacking the insanity plea at the same time, since the break between both proceedings are minimal.
"It's just going to be an involved situation is what it amounts to," he said.
Those who are found to be guilty of the crime and determined insane are sent to a guarded mental health facility. It's not a lax sentence, London said.
"It's an indefinite period of time (in the facility)," she said.
Insane clients can hinder their defense because they potentially can disrupt dialogue with their attorney.
"It's more of a client control and client communication issue," London said.
California Penal Code 25(b) states a person is found insane when he or she is "incapable of knowing or understanding the nature and quality of his or her act and of distinguishing right from wrong at the time of the commission of the event."
Wasserman will be interviewed and evaluated by mental health experts. But the main determination of a person's mental capacity comes from the jury, said Rory Little, a professor at UC Hastings College of the Law in San Francisco.
"The experts usually cancel each other out and the jury is left with their common sense," Little said.
Insanity pleas in America originated from an 1843 British case involving Daniel M'Naughten who thought his misfortunes were instigated by the prime minister. But instead of assassinating the prime minister, M'Naughten, a Scottish woodcutter, mistakenly killed the prime minister's secretary.
Nine people testified he was crazy. The jury acquitted him.
In reviewing the case and the verdict, judges from the House of Lords ruled a defendant can be found not guilty if he or she could not distinguish their crime was right or wrong. The ruling was adopted by the American legal system and followed for more than 100 years with few changes.
In the 1960s and 1970s, changes were instituted on how a person can be determined insane. The American Law Institute established a model to allow psychiatric evidence and lowered the bar on a person's mental state in ascertaining right from wrong.
When Hinkley, who tried to assassinate Reagan, was found not guilty by reason of insanity, it lead to public outcry and the Insanity Defense Reform Act of 1984. The act fell back to conditions used in the M'Naughten case.