Nearly every general who would command at Gettysburg first fought, and befriended his future enemy, in Mexico. The episode follows Taylor's northern campaign and Scott's drive from Veracruz to Mexico City, and the young officers who learned their trade there. It also tells the darker story of the San Patricios, Irish-Catholic deserters mass-executed in 1847, and Grant's verdict that it was among the most unjust wars a stronger nation waged against a weaker one.
The same campaign yields two verdicts: a near-flawless war of maneuver that trained a generation, and, in Grant's later words, a profoundly unjust war. How the officers remembered it was selective and shaped by later loyalties.



