Several states have death penalties for crimes. This is a legal process of killing people. Without an indictment, trial, guilty verdict, and assignment of death penalty, killing is not legal.
Many Christians believe any killing is murder, and therefore those convicted and sentenced to death should instead be incarcerated for life. Mitt Romney is not a Christian and he supports illegal killing of Americans.
Commenting on the illegal killing of an American who did not have a trial, Mitt Romney praised Obama and stated, "I commend the president, the members of the intelligence community, our service members, and our allies ..."