Disfranchisement had far-reaching effects in Congress, where the Democratic Solid South enjoyed "about 25 extra seats in Congress for each decade between 1903 and 1953". Also, the Democratic dominance in the South meant that southern Senators and Representatives became entrenched in Congress. They favored seniority privileges in Congress, which became the standard by 1920, and Southerners controlled chairmanships of important committees, as well as leadership of the national Democratic Party. During the Great Depression, legislation establishing numerous national social programs were passed without the representation of African Americans, leading to gaps in program coverage and discrimination against them in operations. In addition, because black Southerners were not listed on local voter rolls, they were automatically excluded from serving in local courts. Juries were all white across the South.