Penalties - death and otherwise

One of the arguments that's used against the death penalty is that an innocent person could be put to death by the state. This, of course, is why there are so many appeals in the process, so many checks, and so many last moment stays of execution from either the governor or the Supreme Court. The thought of executing an innocent person in error should give us all pause, and it's reasonable to make every effort to determine guilt before carrying out a death sentence.

But is that sufficient reason to eliminate the death penalty? If so, what about a life sentence? Is it acceptable to keep an innocent person in prison for 25 years or more? What if the prosecutor and police actually withheld evidence of innocence in order to make the case?

According to a case now before the Supreme Court, this very scenario occurred and, according to Iowa law, the State can deprive an innocent person of liberty for 25 years (or more!) and once they let that person go, why, no harm, no foul. The freed person goes along his/her way and just starts over where they left off, 25 years ago.

Of course, he might never have won the appeal to prove his innocence before dying in prison because as a person only serving a life sentence without parole there's no real urgency, right?

Some would argue that an innocent person could be paid reparations for the prison time. Apparently not in Iowa, even in the case of prosecutorial misconduct.

So why is the chance of killing an innocent person so heinous that it's a conclusive reason to eliminate the death penalty if it's perfectly acceptable to deprive an innocent person of his/her liberty - and quite possibly let him/her die in prison?