death penalty is a form of justice
liberal societies such as Europe unequivocally call for abolishing death penalty, arguing that it violates the fundamental right - the right to life. further, it is also argued that emotional impulse for revenge does not justify capital punishment, neither is there evidence to support that death penalty is a potent deterrence to crime.
be that as it may, there is another way to look at it.
punishment is seen as a deterrence, but punishment can also be seen as a form of (retributive) justice in itself. why should a person who robbed someone else off their right to life (murder) or right to dignity (rape) be allowed to enjoy these rights? why should we remain so intoxicated on a concocted morality of "protecting sanctity of life" so much that we allow open defilement of it by inhumane elements?
somewhere in the middle east, i think Iran, there was a case of acid-attack on a woman. their justice system involves the victim to decide the course action - punishment or forgiveness, if they so be benevolent. the woman asked for burning the man's face with acid - just as he had done to her. all arrangements were made, the man forcefully held on ground, crying and screaming, acid about to be poured on his face when the lady called it off. she just wanted to give him a taste of the terror.
point being, death penalty honours sanctity of life. it recognizes the uncompromising importance we give to life - that it's violation will put you to death. it's not contradictory.
of course, a critical aspect is the fallibility of justice systems and the fear that an innocent may be executed is the worst imaginable scenario. as is done in India and Taiwan - capital punishment is reserved only for proven crimes of vicious nature.