For several weeks, an 18th century replica ship has traveled across the Atlantic Ocean from France to the U.S. L'Hermione is an exact copy of the vessel sailed by the Marquis de Lafayette in 1780 to notify his friend, General George Washington, that the French king had agreed to provide troops and resources to the flailing Continental Army. This week, the boat is docked in the Washington, D.C. area, fittingly near Mount Vernon, and various French and American entities are feting the occasion. They have good reason. America's first and longest ally is France, despite occasional variances in political dispositions....