The Whiskey Rebellion was a riot in the history of the United States. In 1794, some farmers in Pennsylvania rebelled against the government because of a tax on whiskey. Selling whiskey was how people traded things in Western Pennsylvania, so they thought the new tax was very unfair. The government under George Washington, with advice from Alexander Hamilton, quickly stopped the rebellion. Washington and Hamilton wanted to ensure that no one would question the power of the federal government, so they sent almost 13,000 troops to stop the rebellion of a few hundred farmers, led by President Washington himself. That made the new government more solid, and the President more powerful.
So far, this is the only time in American history that a President has led the Army by himself.