That is not to say that Americans want to abolish the death penalty entirely.

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Yet winning agreement to abolish the death penalty proved more difficult than stamping out slavery.

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This would suggest that those American states yet to abolish the death penalty are cases of arrested development.

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When Nelson Mandela came to power in South Africa, one of the first things he did was to abolish the death penalty.

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O'Malley has most recently pushed for Maryland to abolish the death penalty.

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The US state of Maryland is poised to abolish the death penalty after its lawmakers voted 82 to 56 in favour of the move.

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Of more recent note, Murphy added, Illinois became the 16th state to abolish the death penalty when Governor Quinn signed the bill banning capital punishment in March of 2011.

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Despite this, in the past three decades the international movement to abolish the death penalty has scored the kind of victories which slavery opponents took much longer to achieve more than a century ago.

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The National Coalition to Abolish the Death Penalty plans to work through state legislatures to abolish the death penalty for offenders under age 18 in the 22 states where it is still allowed, said Steven Hawkins, executive director of the group.

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Voters in California are to be asked whether they want to abolish the state's death penalty law.

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