Francis Scott Key's Star Spangled Banner, inspired by Fort McHenry's defense after the burning of Washington, DC, during the War of 1812, reminds Americans of a time when the United States faced a very real foreign invasion.

Arising out of a series of bitter commercial and naval disputes, and having as much to do with perceived slights to national pride as any pressing cause, the War of 1812 was never the most popular of conflicts on both sides of the Atlantic. Bogged down by their involvement in the Napoleonic conflict in Europe, the British largely relied on the power of the Royal...