Can you find any region where Christians once ruled where the church has prospered in the long run? Scan the whole of Europe: England, Sweden, Denmark, and so on. Could anyone dispute that these countries are today on the whole more secular and less open to the gospel than regions that have had little or not contact with the gospel? […] It teaches us that whenever Christians have gotten what so many American evangelicals today are trying to get — namely, the power to enforce their righteous will on others — it eventually harms the church as well as the culture. The lesson of history, a lesson the Devil has known all along, is this: The best way to defeat the kingdom of God is to empower the church to rule the kingdom of the world — for then it becomes the kingdom of the world! The best way to get people to lay down the cross is to hand them the sword!

Gregory A. "Greg" Boyd (b. 1957) American evangelical pastor, Christian theologian, author.

The Myth of a Christian Nation (2007)