The US bowed to international and domestic pressure yesterday, becoming the last country officially to abolish the death penalty for offenders who were under 18 when they committed murder.
The Supreme Court ruling will spare up to 70 inmates who are on Death Row for committing murders while aged 16 or 17, and it removes a frequent source of friction between the US and Europe. The EU was quick to welcome the decision, but said it opposed capital punishment under all circumstances.
The former US president Jimmy Carter said that with the ruling the US had joined "the community of nations".
"The Supreme Court decision confirms recent compelling scientific research findings, that the capacity for curbing impulsiveness, using sound judgment, and exercising self-control is much less developed in adolescents than in adults," Mr Carter said in a statement.
The ruling, passed by a 5-4 majority, was made in the case of Christopher Simmons, who was 17 in 1993 when a woman died after he tied her up and threw her off a bridge in Missouri. The judges ruled that juvenile execution conflicted with the eighth amendment of the constitution which outlaws "cruel and unusual punishment".
"To decide what is cruel and unusual you don't look at what was happening 200 years ago. You look at evolving standards of decency, they said".
Of the 39 executions of child offenders recorded by Amnesty International since 1990, 19 took place in the US. The other countries include Iran, China, Congo, Saudi Arabia, Pakistan and Yemen, but the US was the last government to condone and defend the practice officially. Iran has formulated a law banning such executions, but it has not yet been put into practice.