Since the late 20th century, the county has voted mostly Democratic, but the demographics of political alignments have changed markedly since the 19th century. African Americans have mostly left the Republican Party to support the national Democratic Party. Conservative whites have shifted to the Republican Party. In the 1972 election, Republican Richard Nixon won every county in the state including Marlboro. In state and local voting, many whites have voted for Republican candidates, and African Americans have tended to continue to support the Democrats.