Both federal and state laws regulate elections. The United States Constitution defines (to a basic extent) how federal elections are held, in Article One and Article Two and various amendments. State law regulates most aspects of electoral law, including primaries, the eligibility of voters (beyond the basic constitutional definition), the running of each state's electoral college, and the running of state and local elections. Private sources of finance make up substantial amounts of campaign contributions, especially in federal elections. Voluntary public funding for candidates willing to accept spending limits was introduced in 1974 for Presidential primaries and elections. The Federal Elections Commission, created in 1975 by an amendment to the Federal Election Campaign Act has the responsibility to disclose campaign finance information, to enforce the provisions of the law such as the limits and prohibitions on contributions, and to oversee the public funding of US presidential elections.