Loughner, it is widely assumed, pled guilty as part of a deal: in exchange, federal prosecutors agreed to not pursue the death penalty against him. As Loughner’s plea deal illustrates, capital punishment is sometimes used as a bargaining chip.
As California voters take to the ballot box this November to decide whether to ban the death penalty in the state, some are arguing that they should vote "no" for that very reason.
But is it necessary — or even ethical — to get a guilty plea by holding a gun to a defendant’s head?
There are surprisingly few studies on the topic; even fewer have been published in peer-reviewed journals.
A 2006 Harvard study looked at plea bargains in murder cases before and after New York reinstated the death penalty in 1995. The main question for researcher Ilyana Kuziemko was cost: it’s well known that incarcerating a death row inmate costs more than incarcerating an inmate for life, mainly because of special housing and legal bills. But, Kuziemko asks, does the plea bargain effect of having capital punishment on the table negate some of that cost?
The average death penalty trial, not including appeals, can "cost anywhere from $200,000 to $1,500,000." Trials, in general, are naturally more expensive than court proceedings where a defendant pleas guilty.
Analyzing similar cases before and after capital punishment’s reinstatement, Kuziemko found that more defendants pled guilty to their original murder charges when threatened with the death penalty. However, she found that when the death penalty was on the table, fewer defendants reached deals to plea down to lesser crimes, like second-degree murder instead of first.
Overall, the two effects cancelled each other out, and "did not seem to reduce the total number of cases that proceed to trial." Thus, she concluded, "the well-documented costs of capital trials do not appear to be offset by reducing the total trial costs through plea bargains."
The death penalty, however, "does increase the bargaining position of DA’s."
In another study, researcher Susan Ehrhard interviewed 27 attorneys about specific cases they worked on and what had factored into plea decisions.
Ehrhard found "the consensus among defense attorneys was that the threat to file and pursue a death notice in a murder-one case is the prosecutor’s most powerful tool." Defense attorneys she interviewed said the death penalty loomed large in plea negotiations in murder cases that were eligible for capital cases.
In fact, defense attorneys largely said they were more likely to ask for plea deals in capital cases. In cases where life without parole was the maximum sentence, however, they were more inclined than in capital cases to risk trial rather than take a lesser sentence.
Most prosecutors interviewed said they did not deliberately threaten death in order to encourage a plea deal, but said they’d heard of other prosecutors who do. Moreover, "ten defense attorneys and ten prosecutors said defendants plead to a lesser sentence to avoid the possibility of death."
Overall, Ehrhard, concluded, "while the death penalty may act as a tool in processing cases efficiently and cost-effectively, there are ethical and potentially human costs to consider in using the death penalty as leverage."