New York's political pattern changed little after the mid–19th century. New York City and its metropolitan area was already heavily Democrat; Upstate was aligned with the Republican Party and was a center of abolitionist activists. In the 1850s, Democratic Tammany Hall became one of the most powerful and durable political machines in United States history. Boss William Tweed brought the organization to the forefront of city and then state politics in the 1860s. Based on its command of a large population, Tammany maintained influence until at least the 1930s. Outside the city, Republicans were able to influence the redistricting process enough to constrain New York City and capture control of the Legislature in 1894. Both parties have seen national political success: in the 39 presidential elections between 1856 and 2010, Republicans won 19 times and Democrats 20 times.