The amount of military detail handled personally by the president in wartime has varied greatly. George Washington, the first U.S. president, firmly established military subordination under civilian authority. In 1794, Washington used his constitutional powers to assemble 12,000 militia to quell the Whiskey Rebellion—a conflict in western Pennsylvania involving armed farmers and distillers who refused to pay an excise tax on spirits. According to historian Joseph Ellis, this was the "first and only time a sitting American president led troops in the field", though James Madison briefly took control of artillery units in defense of Washington, D.C., during the War of 1812. Abraham Lincoln was deeply involved in overall strategy and in day-to-day operations during the American Civil War, 1861–1865; historians have given Lincoln high praise for his strategic sense and his ability to select and encourage commanders such as Ulysses S. Grant. The present-day operational command of the Armed Forces is delegated to the Department of Defense and is normally exercised through the secretary of defense. The chairman of the Joint Chiefs of Staff and the Combatant Commands assist with the operation as outlined in the presidentially approved Unified Command Plan (UCP).