Anthony Comstock was a United States politician who led a moral crusade against anything he believed to be "obscene"…including birth control.

A Civil War veteran of the Union Army, he arrived in New York City after the war and was shocked by levels of prostitution and pornography in the city. He made a name for himself with his "anti-obscenity" stances and actions and arrived in Washington, D.C. in 1872 with a draft of the Comstock Act, which Congress passed on March 3, 1873. Twenty-four states passed their own versions of the act. Altogether, the state and federal statutes are known as the Comstock Laws.

Among bans on pornography and any other "obscene" materials, the Comstock Act bans:

...any drug or medicine, or any article whatever, for the prevention of conception, or for causing unlawful abortion, or shall advertise the same for sale, or cause to be written or printed, any [...] notice of any kind, stating when, where, how, or of whom, or by what means, any of the articles in this section can be purchased or obtained...he shall be imprisoned at hard labor in the penitentiary [...] or fined. (Source)

Margaret Sanger offered specific challenges to the Comstock and they were amended many times…since as what constitutes "obscene material" went on to be redefined in court case after court case throughout the 20th century.