http://www.bbc.co.uk/news/world-us-canada-27265443

For various reasons they seem incapable of carrying out the executions for one thing!

Even if you do agree with it in principle, I understand the costs the government of funding appeal after appeal is higher than the cost of just leaving them in jail for the rest of their lives. Purely from a financial point of view they should be stopped. That's before you get onto the issues of miscarriages of justice, racial bias in its application etc.