1.   Back then, the state of Arizona had no problem executing mentally retarded murderers.

2.   Citing a growing national consensus and evolving standards of decency, a divided Supreme Court Thursday banned the execution of mentally retarded murderers.

3.   The ruling applies to only mentally retarded murderers.

4.   The court will decide this month if it is cruel to execute mentally retarded murderers and if judges, instead of juries, can sentence someone to death.