That link was about the legal issues surrounding a murder case. It was not about inflicting the penalty

You mean this one which clearly explains that the cost for death penalty is significantly higher than life in prison?

Which is more just

Nevermind the fact that your numbers are your own estimations. Since this link which explains that the cost of the drugs used for executions has spiked because (surprise!) no company wants to be known for selling death drugs. Some states use up to a three drug combination for lethal injection, which means they are already well above your estimation without factoring defense counsel, court fees, and higher death row incarceration costs.

Also, what definition of "just" are you using? Are you taking a unilateral approach? An economic approach?

I would really much rather spend the money making sure we get it right the first time than cross our fingers and hope that the passage of time partially corrects our mistakes.

All you want is a rush job then (comparitively speaking, because the legal system is not fast). And what exactly are you defining as "the first time?" An appeal is generally referred to as a "second bite at the apple."

Because we have fewer live murderers running around killing innocent people (or at least redeemable people in jail).

See, the fact that you even make that statement is another perfect example of why we should not have a death penalty. Whose standards are we going by? Obviously you draw a line between murder and some other crimes to judge a person redeemable or not. It's totally subjective where that line gets drawn. Why not just draw it at law abiding? Then you have less criminals going around doing criminal things to innocent people.

If our system is biased when dealing with free people accused of crimes, what on Earth makes you think it will suddenly correct itself dealing with the same people after conviction?

Because of groups like this that are triple checking and investigating cases to try and fix the errors in the system.

None of those people received justice, even in the absence of a death penalty.

Again, how are you defining justice? And does the fact that these wrongly convicted people were released but couldn't be given back their time spent in jail mean that we should support the death penalty? Just because the system is fucked up doesn't mean we should go all in on the fucked up-ness.