Lisa Sharon Harper, director of mobilizing at the progressive Christian justice organization Sojourners, represents the left, and D.C. Innes, associate professor of politics at The King’s College, stands in for the right.

"Both of us are Christians. And so what we have in common is greater than all our differences," Innes and Harper write. "Yet differences there are, and in this book we elaborate on our political differences. How can two people who share the same fundamental life-transforming Christian principles think so differently when it comes to politics?"

The authors tell how they arrived at their current political stances, both led by their understanding of Christian teachings. Innes, an ex-pat Canadian Tory turned American Republican, says "the Christian view of man prompted me to move toward the modern Republican view of politics as the most prudent way for fallen people to live with one another politically." Harper, whose ancestors are African, Native American, and Puerto Rican, says her evangelical faith shapes her liberal perspective on today’s issues: "We the people will be called to account for the effect of our public policies on the least of these in our society. Did we bless or did we curse?"

From their divergent perspectives, Innes and Harper explore how Christian faith shapes one’s participation in the political process. They argue their positions on issues including poverty, health care, immigration, same-sex marriage, abortion, terrorism, and the environment, in a robust yet respectful give-and-take.

They have markedly different opinions on the role of government, which color their views on the other issues up for discussion. Both find a biblical mandate for their belief, Harper in a "hands-on" government working to make life better for citizens, and Innes in a "hands-off" government that punishes evil and encourages citizens to do good, but doesn’t provide for every need.

Harper and Innes agree that the Bible emphasizes the moral responsibility of people to care for the poor among them. "Christians in America are to help make it a better place in every respect: more just, more equitable, more merciful, more wise, more beautiful, more fruitful, more flourishing in every way that God desires human communities to flourish." They differ, sometimes widely, in their understanding of how to get there.