I don't think so. This is an arbitrary sense of morality. To hold that all life is sacred is a mistake, because some lives are more sacred than others, and some lives prove to be absolutely worthless.
For the most heinous crimes, like that of Luka Magnotta, who had fun killing someone - and letting the offender live while the victim dies, and the parents and loved ones experience the loss for the rest of their lives.... I think letting such a person live is barbaric. Death is sometimes a JUST punishment.
As for some lives are more sacred than others, many who oppose capital punishment also support a woman's right to abortion. In abortion, a human life is terminated and that life is taken away arbitrarily, without a court, without a higher authority, solely at the discretion of the mother. Not only that, that life has never done anything wrong. If you support abortion, you support the termination of a life. Why would one support terminating an innocent life when at the same time they can't support terminating a life that has proven to be evil?