Political advertising is usually sponsored by the candidates and parties who seek election or reelection to political office. However, in the United States, where free speech is a valued right, political advertising is often sponsored by independent groups or individuals who wish to advocate for the election or defeat of individuals, parties, or ideas or issues. Such advertising has always been possible in print form, but growth of electronic media, radio and television, and later the Internet provided additional means and channels for these messages. Independent advertising also provided an outlet for corporations and labor unions that are prohibited from contributing to political campaigns in the United States.

Television advertising by groups independent of the candidate's campaign became nationally visible in Richard Nixon's 1972 campaign when ...