[jlkrusty]

Here's one consideration hardly ever anyone mentions:

5. How important is it to keep capital punishment to have something to plea bargain with the defendant?

Capital punishment gives the prosecutor something to bargain with. Very often the defandant strikes a plea with the prosecutor and admits how he committed his murder(s) in order to avoid the death penalty. This saves the ordeal of a very costly and emotionally draining trial (especially on the victim's family). Without the death penalty, we'd lose this valuable bargaining chip.