First of all lets make clear that these are my views and only mine, also I warn that they require the correct attention and understanding otherwise I may come across as some kind of self-appointed king.
As a deterrent alone, the death penalty should be in place everywhere, certain crimes are so evil to certain societies that the menace of losing your life is more than justifiable for the rest of your group; actually we shouldn't have the right of stopping this just because, I don't know, maybe we are stronger or more clever and assume we can defend ourselves, others can't and need the assurance of knowing that before someone considers to harm them, they have to consider what's at stake.
For me it's all about redemption, a mass murderer can not be given the death penalty and a shoplifter can, it all depends on what you can redeem out of them, that redemption has to be very well defined, a clear line with no doubts, so clear that once passed, medical issues excluded , there would be no need for the expenditure of a trial.
A man furious with the hand he was dealt, goes on a rampage destroying everything on his path, armed with a lifetime of misfortune and well aware that death can be the punishment for his actions, but as far as I am concerned we can salvage something from that person, putting an end to the death penalty option, in the right setting, with a few bad decisions changed, that man can produce something, he is redeemable, his horrific day out can be made sure of never again being repeated.
A few years back my friend at Uni. was jumped by two blokes, if you go to rob a student unless you know something we don't, it might give you away as not very bright since students are skint most of the time, nevertheless they went wallet, watch, jewelry , my friend is a very candid person and obeyed in full, and just as all three were about to get on with their lives, the second robber said to his mate, "cut him, cut him", by luck or common sense he didn't but that other person deserves the death penalty regardless of the crime because there is nothing that can be redeemed about him.
One day oxygen will be rare and that boy took some he didn't deserve, and now we need it and don't have it, someone that in the commission of a crime proceeds to, for no reason, to hurt his victim, well I'm sorry but those are the cases that the death penalty should be applied without a trial,except of course if he is medically insane.
It's nice to be politically correct and avoid certain issues, but in all truth if we don't face up this life facts up front when we go to face them at their end it will be too late, lets realize that that boy that wanted to cut my friend has nothing good to bring to the world therefore his presence is not needed in the world, do it now and we will at the least not have to fit his bill, or do it when you decide that he has done enough damage, that you won't be able to fix .
For me the death penalty can make the world a better place for those that deserve it, by deterring criminals from certain actions and by delivering the ultimate punishment when justified, a crime turned violent for the sake of it should get maximum penalty with no need for a trial just for the sake of it.