Americans like to think of our nation as exceptional in nature, a dramatic break from all that came before it. Being exceptional, it’s inconvenient to acknowledge that two European powers provided invaluable assistance in our struggle for independence from Britain. So we usually don’t. The American origin story thus has scrappy colonists fighting the British alone, with little outside help except for France’s Lafayette, and a cameo by General Rochambeau at the very end. But Americans could have never won …