I finished reading City of Man: Religion and Politics in a New Era a couple of weeks ago, and I’ve been sitting on it, mulling it over, ever since. It’s an important book, warranting a great deal of careful thought, and it’s also one of those rare books on US politics that actually does more to promote civil discourse in the public square than to erode it.

The book’s authors, Michael Gerson and Peter Wehner, are both conservatives — and political insiders at that. Gerson, as you may know, was a top aide and speechwriter for George W. Bush. He’s also a syndicated columnist for the Washington Post, and a senior advisor at ONE. Wehner is a senior fellow at the Ethics and Public Policy Center, a DC think tank. He previously served in the Reagan and Bush (I and II) administrations.

The central question of the book is one both urgent and timeless:

What does it mean to be a Christian citizen in history’s most influential nation; in a world marked by growing interconnection, danger, and need; in a time of bitter domestic polarization and economic stress?

The first part of the answer is that there are more than two political options, odd as that may seem to us in twenty-first century America. As Gerson and Wehner write, Christians throughout history have formulated quite an array of differing — and, in some cases, diametrically opposed — political approaches that can’t be summed up by the overly limiting categories of right and left. Here are some of the main ones:

• Constantinian: “wanted the church to govern earthly affairs, so as to bring society better into line with their understanding of God’s will.”
• Augustinian: “the purpose of the state is to restrain evil and to advance justice.”
• Anabaptist: “Christian allegiance should be to the kingdom of God alone.”
• Lutheran: “two kingdoms, one carnal and the other spiritual, each needing to remain separate from the other and each making its own legitimate demands.”
• Calvinist: “God [is] not only Lord and Creator but ‘a Governor and Preserver…’ The sovereignty of God, in other words, extends to all spheres, including all human institutions.”
• Kuyperian: “three spheres — the Church, the State, and Society — each distinct but interrelated with the others, all part of the created order, all governed by God.”
• Barthian: “the state… like the church, served Christ’s divine purposes beyond simply restraining evil.”
• Niebuhrian: “believed in the necessity of politics in the struggle for social justice.”
• Falwellian: “restoring America’s ‘moral sanity’ as an urgent Christian imperative.”

For that survey alone, the book is more than worthwhile. But that’s just the first chapter. Gerson and Wehner go on to outline, with conviction and grace, broad principles for Christian participation in politics. As conservatives, they take predictable stances on a variety of issues, but as Ron Sider writes in his endorsement on the book jacket, “one need not agree with all the assumptions or arguments to find this book a significant contribution to Christian reflection on where our nation should go.”

Politics, they write, presents us with an “unavoidable tension”: while a politicized faith has its dangers, “there is also moral abdication when faith ignores the opportunity for ‘genuine ethical action,’” a term borrowed from John Perkins. They point out the failures of the Religious Right, and urge us not to make the same mistakes — whether on the right or on the left. Rather, they urge discernment, faithful engagement, and above all, an emphasis on persuasion rather than attack. “If you would win a man to your cause,” said Abraham Lincoln, “first convince him that you are his sincere friend.”

In a polarized political climate that is anything but civil, in which demonizing and mudslinging are the norm, where cable news channels teach us that the way to discuss politics is to see who can yell the loudest, a book like this is a breath of fresh air. It’s practical, and true to both theology and history. Borrowing from Augustine, Gerson and Wehner conclude with both determination and hope: “The City of Man is our residence for now, and we care for its order and justice. The City of God is our home.”