Copperhead Democrats were a faction of the Democratic Party in the Northern United States during the Civil War, known for their opposition to the war and advocacy for peace with the Confederacy. They were labeled 'Copperheads' by their opponents, who viewed them as traitors for their anti-war stance, which often included criticism of Abraham Lincoln's administration and its policies. This group emerged as a significant political force, especially in the Midwest, as they sought to end the conflict through negotiations rather than military action.