War begets war: it is an old truism, and internecine wars — of the type twice fought on American soil — typically have their antecedents in prior wars. Consider our Revolutionary War, whose cri de coeur was “no taxation without representation.” But how often we overlook that Britain imposed these heightened taxes on the colonists to service debts from the French and Indian War. Consider our Civil War, which was fought to preserve the Union and abolish slavery. But how often we overlook that what upset the balance between free and slave states were territorial acquisitions made during the Mexican-American War. This pattern extends also to the key personalities of these conflicts, who first appeared on the historical stage in the prior war — George Washington, who at the end of the French and Indian Wars was a minor officer of mixed reputation who had once surrendered to the French, and Ulysses S. Grant, who mustered out of the army not long after the end of the Mexican-American War. When Robert E. Lee surrendered to him seventeen years later at Appomattox, Grant reminded Lee that they had met once before, in Mexico. General Lee, who had been a colonel in that first war, apologized; he could not recall having ever met Grant.