Just how much more depends on where you are but even more on how you count the dollars.
Here's why how you count matters, and let's just do this with round numbers to make it easy. Suppose that the cost totals 2 million dollars for the investigation, prosecution, incarceration, post-trial litigation, clemency proceeding, and execution of Real Bad Guy. OK, we can try to measure that against the costs that would be run up if he'd just been charged and convicted of the same crime but with only an LWOP (life without parole) sentence as a possibility. Total cost, say 1 million dollars. That way of counting is easy and the cost is clear. Death costs a million.
But the state is spending money not only to get Mr. Guy killed. The state is also spending money for the capital prosecution of his co-defendant, Mr. Evil Son Bitch. If he gets death but a last minute reprieve, the state may have spent 2 million dollars but got only a million dollars worth of benefit. Or what if he got life from the start? More cost, no effect. Where does that cost factor into the equation? Those aren't costs for killing Guy, but they're costs for having the system.
And the upfront costs are high. Capital cases get more police attention, more prosecutor attention. More experts are hired (on both sides). Defense costs are greater. Pre-trial incarceration is longer and takes more judicial resources as more motion work is filed and more hearings are held. Lots more investigation by everyone. It takes longer to pick a jury, longer to try a case, and there are essentially two trials - one to determine if the defendant is guilty and one to determine sentence. And if he's not guity of the capital charge or sentenced to life, all that extra expense - or at least some of it - served no fundamental purpose.
Kent Scheidegger of the Criminal Justice Legal Foundation says all that's OK because it's worth the cost. We should have the death penalty, he says, for all sorts of reasons. If it costs more, so be it. He wants more people sentenced to die and more executed. But he also thinks the death penalty is important because it makes it easier to impose LWOP by plea bargain, which ultimately saves money.
Having the death penalty can offer powerful incentives in plea bargaining, Scheidegger said, and could provide states with large savings in trial and incarceration costs.I disagree with Scheidegger about many things, but I respect at least his commitment to the position that death is an appropriate sentence in many cases. I can't say the same for his argument about plea bargaining.
Plea bargaining is about resolving cases. We do it because the alternative is both impossible (there truly aren't the resources to try every case) and undesireable. A plea bargain, after all, reduces everyone's risk. It's like a settlement in a civil case. Everyone gives up something in exchange for certainty of outcome. (And speed, but that's really a separate issue.)
The problem comes when prosecutors charge high with the intention of bargaining down. First, it taints the system because the charges aren't what they should be. Prosecutors are supposed to seek justice. If they think LWOP is the proper sentence, then they should pursue LWOP. If they think LWOP is the proper sentence but they think the way to get there is by charging death, then they're risking gettiing someone killed who they've concluded should be getting LWOP.
When LWOP is the negotiated consequence of a fairly selected capital charge (assuming there were such a creature), then so be it. But when LWOP is the goal of a capital charge, then the charge - and the attendant risk if the prosecutor's hoped for/expected deal doesn't go through - is simply an abuse of power.
S, at Preaching to the Choir, who pointed me to the CNN story, says the cost is necessary if we're going to ensure that we don't kill the wrong people, that we care about killing the wrong people, and that the reasonable solution is to save money and stop killing people.
I'm not sure, alas, that I agree with her assessment that our collective distaste over the prospect of killing the innocent and otherwise placating the public with a sense of fairness is such that we will insist on the protections that drive up that cost. I think that's part of it. Part of it is that the system is so heavily weighted. Capital cases draw high publicity which makes prosecution extra-necessary and efforts to secure death doubly expensive. That's not about protectiing anything - it's about ensuring a verdict. But that brings costs on the other side.
It's a mess. But we know that about death.