Rich Lowry

Gen. George Washington’s army retreated from New York in ignominy in November 1776. As it moved through New Jersey, Lt. James Monroe, the future president, stood by the road and counted the troops: 3,000 left from an original force of 30,000.

In December 1776, the future of America hung on the fate of a bedraggled army barely a step ahead of annihilation.

The Americans confronted about two-thirds of the strength of the British army, and half its navy, not to mention thousands of German mercenaries. The defense of New York was barely worthy of the name. When British troops crossed into Manhatta...