Edward P. Costigan was born July 1, 1874. He graduated from Harvard University in 1899 and began work as a lawyer in Denver in 1900.

Costigan was a founding member of the Progressive Party in Colorado in 1912, but lost the election for governor.

Woodrow Wilson appointed Costigan as a member of the United States Tariff Commission in 1917. He was elected to the United States Senate as a democrat in 1930. Oscar L. Chapman managed his campaign.

Costigan and Robert F. Wagner agreed to draft a bill that would punish the crime of Lynching. In 1935 attempts were made to persuade Franklin D. Roosevelt to support the Costigan-Wagner Bill. However, Roosevelt refused to support a bill that would punish sheriffs who failed to protect their prisoners from lynch mobs. He believed that he would lose the support of the white voters in the South, and therefore lose the 1936 presidential election.

The Costigan-Wagner bill received support from many members of Congress but the Southern opposition managed to defeat it. However, the national debate that took place over the issue helped to bring attention to the crime of lynching.

Costigan died on January 17, 1939.