I had heard about Greg Boyd. He is a pastor who made the news in recent years because he preached a series of sermons that caused twenty percent of his church to leave in upset during one sermon series. It wasn’t the typical reasons that people leave churches that you often hear about today like traditional v. contemporary or liberal v. conservative. 
It was due to the fact that he preached on a topic that later became a book called The Myth of a Christian Nation: How the Quest for Political Power is Destroying the Church. He challenged the notion that America is (or ever was) a Christian nation. If you have ever been in an American church and observed the co-mingling of nationalism and Christianity (I have observed it first-hand having visited and preached in American churches on the July 4th weekend) you can easily imagine how this would be upsetting to many people.
This is a really good book. It is much easier for Canadians to digest than our friends south of the forty-ninth parallel. I don’t think we think of ourselves in the same nationalistic ways in Canada and most of us don’t consider ourselves a Christian nation. I have always been uncomfortable when church people have asked to be vocal regarding political parties and political causes and this book helps me sort out my discomfort and theology on these matters.
Boyd says, the kingdom of this world is fundamentally different from the kingdom of God and we must be zealous and watchful to keep the separation clear and distinct. The value of this book is that Boyd does well in reminding us of the contrasts between the two kingdoms—the kingdom of the world and the kingdom of God. In much of his writing he attempts to lay bare the underlying assumptions of each kingdom and that most of our thinking on this matter comes from a Constantinian view of power (the sword) and the church.
I could not agree more with the thesis of the book. I love Canada but it is not where my ultimate citizenship exists … that is the kingdom of heaven.