Holy war can seem like something that happened long ago or that happens far away — the Crusades of medieval Europe, for example, or jihadists fighting secular forces today. But since their country's founding, Americans have often thought of their wars as sacred, even when the primary objectives have been political.
This began with the American Revolution. When colonists declared their independence on July 4, 1776, religious conviction inspired them. Because they believed that their cause had divine support, many patriots' ardor was both political and religious. They saw the conflict as a just, secular war, but they fought it with religious resolve, believing that God endorsed the cause.
As Connecticut minister Samuel Sherwood preached in 1776: "God Almighty, with all the powers of heaven, are on our side. Great numbers of angels, no doubt, are encamping round our coast, for our defense and protection."