two-party system By wiattb001 May 27, 1787 Began at the Constitutional Convention 1820 Jeffersonian Republicans/ Democratic-Republicans They were unopposed in gov't until 1820s 1820 Andrew Jackson's Democratic party came to power May 13, 1865 Democrats crippled by the war 1940 Republicans ran the country for the next 75 years 1940 Rights Democrates scared republicans would give African Americans more rights and dems. dominated the south for next 100 years