The man had argued that his inability to understand the nature of his acts at the time that they were committed should be a sufficient basis for showing that he lacked the requisite mental state required as an element of the charged crime.

[1] In the case, Eric Clark shot and killed a police officer at a traffic stop because he believed his town in Arizona had been taken over by aliens.

Throughout the court case, Clark presented an elaborate testimony describing his odd behavior a year prior to the incident.

However, he dissented from the majority's opinion and would change the case so that Arizona courts could determine whether state law is consistent.

In dissent, Justice Kennedy stated that it was not necessary for him to address Clark's due process challenge to Arizona's insanity test.

[3] There was no controversy either that Clark actually believed that there were aliens who were out to get him, as he hung fishing line in his room as "booby traps" as well as wind chimes on the doors and windows to warn him of intruders.

[3] Lastly, Clark kept a bird in his car to warn him of different changes in air temperature, which he believed could lead to possible intruders.

The state believed that the music was meant to lure the officer to his vehicle with a nuisance offense, as Clark had mentioned to a friend that he wanted to shoot a cop.

[3] The defense expert, Dr. Morentz, dismissed that theory and believed Clark was playing music loudly to "drown out" the voices in his head, a tactic common among people with paranoid schizophrenia.

In 1843, Daniel M'Naughton was diagnosed with paranoid schizophrenia and thought that he was being persecuted, causing him to shoot and kill Edward Drummond.

[9] The outrage after the court decision caused four states to eliminate the insanity defense: Montana, Utah, Idaho, and Kansas.