10 June 2008 :

in the United States, Virginia Gov Timothy Kaine stopped tomorrow's execution of Percy L Walton and commuted his sentence to life in prison without parole, saying that Walton is mentally incompetent and putting him to death would be unconstitutional.
In a statement Kaine said he cancelled the execution because "one cannot reasonably conclude that Walton is fully aware of the punishment he is about to suffer and why he is to suffer it.''
Walton pleaded guilty in 1997 to killing Jessie and Elizabeth Kendrick, an elderly Danville couple, and his neighbor Archie Moore. His attorneys have contended for years that Walton is mentally ill and that his condition has further deteriorated since he has been on death row.
Kaine had delayed Walton's execution in 2006 to allow for an independent evaluation of his mental condition and competence. Based on that evaluation, the governor delayed the execution another 18 months, saying that Walton was severely mentally impaired but that it was possible his condition would improve.
The US Supreme Court ruled in 1986 that execution of the mentally ill violates the constitutional prohibition against cruel and unusual punishment. The court said death-row inmates must be able to comprehend that they are about to be executed and why.