The Nevada Assembly voted Monday to bar executions of criminals who are mentally retarded or under age 18.
There was no discussion as the Assembly approved the bills, along with a third measure giving the defense the last word in the sentencing phase of capital cases.
Approved on a 36-6 vote, AB118 would eliminate the state's ability to seek the death penalty in cases where the defendant was less than 18 years old at the time of the crime.
During Assembly Judiciary Committee hearings on AB118, David Fassler, a University of Vermont professor who specializes in child psychiatry, describe major changes that the human brain undergoes during adolescence.
Fassler said that because of those changes, youths 16 to 18 years old often rely on a part of their brain, the amygdala, that controls instinct rather than the frontal cortex, which controls reasoning, planning and judgment.
One man currently on Nevada's death row was convicted as a juvenile. Michael Domingues was 16 in 1993 when he killed Arjin Pechpho, 24, and her 4-year-old son, Jonathan Smith, at their home in Las Vegas.
Under the bill, Domingues' sentence would be commuted to life in prison.
The Assembly voted unanimously for AB15, which would prohibit a judge or jury from sentencing a mentally retarded person to death.
Under the bill, defense attorneys claiming their client is mentally retarded would have to make that client available to an expert chosen by the prosecution. Both sides would then make their arguments to the trial judge.
Lawyers for the state and defense could cross-examine one another's witnesses, and the hearing on mental retardation would parallel trial proceedings.
Mentally retarded would mean "significant subaverage general intellectual functioning which exists concurrently with deficits in adaptive behavior and manifested during the developmental period."
The chamber also unanimously approved AB14, which gives the defense the opportunity to open and close the arguments during the penalty hearing of a death penalty case.
Advocates said that allowing the prosecution to argue first and last, while appropriate during the trial phase, gave the state too strong an advantage when determining whether the convicted person should be executed.
AB14 also adds mental illness to the list of mitigating circumstances that must be weighed when considering whether to impose a death sentence.
A jury or judge must determine that any aggravating factors outweigh any mitigating circumstances before a death sentence can be imposed.
All three bills now move to the Senate for its consideration.