Death sentence
"Death sentence" and "death penalty" were equally common names for the capital punishment of execution — the state-sanctioned death of an individual in recompense for crimes of an especially grave nature, such as murder or treason. Sometimes, especially in Earth's past, or in places without clear governmental structures, it could be carried out against people for less profound crimes, or even arbitrarily.
Earth
On Earth, it was a divisive issue. Some parties, such as the Briton, Professor Kettering, believed that the death penalty was a backwards conception of justice. (DW: The Mind of Evil) To the contrary, many Americans in Jacksonville, Kentucky on "Miracle Day" fully believed that the rapist and murderer Oswald Danes should not have been paroled after his death by lethal injection failed. (TW: The New World)
Indeed, there was a general divide between the British and American viewpoints on the issue. The death penalty was abolished in the United Kingdom at least by the late 20th century, whereas it was still an acceptable punishment in at least the state of Kentucky as late as the year 2011. (DW: The Mind of Evil, TW: The New World)
Centuries before, in the dukedom of San Martino, the government sanctioned execution, and once nearly beheaded the Fourth Doctor. (DW: The Masque of Mandragora)
Elsewhere
Elsewhere in the universe, the death penalty was known to be used by the Raxacoricofallapatorians. Blon Fel-Fotch Passameer-Day Slitheen, for instance, was tried and sentenced to death in absentia. The Ninth Doctor, who had captured her in Cardiff and wanted to extradite her back to Raxacoricofallapatorius, was therefore faced with the moral dilemma of whether he could become, in effect, her executioner. (DW: Boom Town) Time Lords exercised the death penalty, largely for crimes against the Laws of Time. The penalty for setting one's self up as a god in a more primitive civilisation, for instance, was vapourisation. (BFA: False Gods) The death penalty on Gallifrey was sometimes effected through a so-called "Warrant of Termination", such as was served on the Fifth Doctor. In that instance, however, he wasn't threatened with death because of any actual wrongdoing, but because he had become controlled by a malevolent entity that posed a grave risk to the entire universe. (DW: Arc of Infinity) Later, the Fifth Doctor and Peri were nearly executed by firing squad on the planet Androzani Major by the authority of the quasi-governmental Sirius Conglomerate. (DW: The Caves of Androzani)
