In 1993, the Supreme Court established that the test used in trials — a defendant’s ability to both understand and assist his lawyer — also applies to guilty pleas.
“The whole process is supposed to be designed to make sure there is an assessment if the defendant is unfit, and then everything grinds to a stop,” said Mark Heyrman, a professor at the University of Chicago Law School who specializes in mental health law. “If a defendant is unfit, there cannot be a trial and there cannot be a guilty plea.”
But that standard has limitations. Jerry Frank Townsend was 27 in 1978 when police officers picked him up in connection with the rape of a pregnant woman on a Miami street. He was described as having the mental capacity of an eight-year old. Nevertheless state psychiatrists ruled him competent.
Most lawyers don't learn anything about mental illness or disabilities in law school, said Heyrman, the University of Chicago Law School expert, and so may fail to recognize their clients’ disabilities and raise the issue.
Read more at Injustice Watch