When Woodrow Wilson went to Congress to ask for a declaration of war in 1917, the U.S. Army was ranked 17th in the world, behind Portugal. On Armistice Day, 19 months later, there were 2 million doughboys in France, where they had helped to break the back of Gen. Ludendorff's theretofore invincible army in its final offensive, and 2 million more in the United States ready to march on Berlin. No other nation could have done that. After Japan attacked Pearl Harbor in 1941, FDR demanded that a disarmed America "build 50,000 planes" -- a seemingly impossible number, but one...