The easiest part of your question:
STATES WITH THE DEATH PENALTY (35)
Alabama, Arizona, Arkansas, California, Colorado,
Connecticut, Delaware, Florida, Georgia, Idaho,
Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland,
Mississippi, Missouri, Montana, Nebraska, Nevada,
New Hampshire, North Carolina, Ohio, Oklahoma, Oregon,
Pennsylvania, South Carolina, South Dakota, Tennessee,
Texas, Utah, Virginia, Washington, Wyoming
Plus U.S. Military & U.S. Gov’t
In 2009, there were 52 executions, carried out by just 11 states:
South Carolina 2
You asked about the economics. Study after study has shown that the death penalty costs much more than life in prison. The high costs of the death penalty are for the complicated legal process, with the largest costs at the pre-trial and trial stages. The point is to avoid executing innocent people. The tremendous expenses in a death penalty case apply whether or not the defendant is convicted, let alone sentenced to death.
Here are a few examples of trial costs (death penalty and non death penalty cases, California):
People v. Scott Peterson, Death Penalty Trial
$3.2 Million Total
People v. Rex Allen Krebs Death Penalty Trial
$2.8 Million Total
People v. Cary Stayner, Death Penalty Trial
$2.368 Million Total
People v. Robert Wigley, Non-Death Penalty Trial
This data is for cases where the best records have been kept.
I believe the death penalty is bad public policy. It doesn’t prevent or reduce crime, costs a whole lot more than life in prison, and, worst of all, risks executions of innocent people.
At the least, the Supreme Court should ban the execution of people with serious mental illness. The requirement is that the condemned person has to be sane enough at the time of the actual execution to know what is happening and why. On at least one occasion, this has been accomplished by forcibly medicating the prisoner. Part of the appeals court which allowed this stated that death is the only unwanted side effect of the medication. This attitude speaks for itself.