 Certain crimes, such as murder, have been considered by the common law of most Commonwealth jurisdictions as so heinous as to be excepted from this doctrine, which is sometimes considered paradoxical in light of the fact that a mere provocation can serve as a partial defense to such charges.In the United States, if a person of ordinary firmness would be deterred by a reprisal from exercising his First Amendment rights to freedom of speech, then this reprisal is considered to have a chilling effect, and it is unlawful for the government to engage in it.Some individuals are not deterred by such reprisals, but rather are riled up by them, and their determination to speak out is increased.