 Chapters of Red Shirts, a paramilitary group working for the Democratic Party that sought to disrupt and suppress Republican voting, helped Democrats win seats in Mississippi and the Carolinas.In 1876 Chalmers was elected as Representative from Mississippi's 6th congressional district to the Congress of the United States, serving in the Forty-fifth and Forty-sixth Congresses, from March 4, 1877 – March 3, 1881.His Republican opponent John R. Lynch contested the victory, as he was previously strongly elected from this black-majority district.