State governments have had the right to establish requirements for voters, voter registration, and conduct of elections. Since the founding of the nation, legislatures have gradually expanded the franchise (sometimes following federal constitutional amendments), from certain propertied white men to almost universal adult suffrage of age 18 and over, with the notable exclusion of people convicted of some crimes. Expansion of suffrage was made on the basis of lowering property requirements, granting suffrage to freedmen and restoring suffrage in some states to free people of color following the American Civil War, to women (except Native American women) in 1920, all Native Americans in 1924, and people over the age of 18 in the 1970s. Public interest groups focus on fighting disfranchisement in the United States amid rising concerns that new restrictions on voting are become more common.