The American System was an economic plan that played an important role in American policy during the first half of the 19th century. Rooted in the "American School" ideas of Alexander Hamilton, the plan "consisted of three mutually reinforcing parts: a tariff to protect and promote American industry; a national bank to foster commerce; and federal subsidies for roads, canals, and other 'internal improvements' to develop profitable markets for agriculture". Congressman Henry Clay was the plan's foremost proponent and the first to refer to it as the "American System".