The Contested Public Square by Greg Forster is “an introduction to Christian political thought,” with a special focus on “the political effects of the Reformation and the Enlightenment in Western Europe [and America].” It traces the evolution of that theory through eight critical junctures in church history.

 

Chapter 1 examines “how persecution permanently shaped Christian political ideas” by forcing the early church to develop “an apolitical sense of its own identity.” As was true of Jesus, the church neither possessed nor sought access to the halls of power, whether in the Jewish Sanhedrin or Roman empire. Rather, its theology subverted the importance of the state.

 

Christianity believes that its religious institution (the church) is eternal and will survive intact after the destruction of the universe and the end of time itself; however, it believes that political institutions (the state) are merely temporal agencies that keep the peace and enforce justice in this world; they will vanish when the world does.

 

This theology both allowed the early church to survive and left it without a blueprint for political engagement. The Old Testament had such a blueprint, but the early church thought that Mosaic law was applicable specifically to Israel, not generally to the nations. The New Testament social teaching applied specifically to the church. If the church were to have a voice in political matters, it would have to utilize non-biblical sources.

 

The primary non-biblical source to which Christian theologians turned was philosophy, the subject of Chapter 2. “Critically and rigorously engaging with the Greco-Roman philosophical heritage helped them both to find answers to questions that the Bible did not answer and to address themselves on politics to those who did not believe the Bible.”

 

Chapter 3 examines the most influential Christian theologian to engage the philosophers on political questions, Augustine of Hippo, whose City of God is arguably the most important Christian work outside of the Bible. Augustine made several important contributions to Christian political thought in this book.

 

First, Augustine outlined a psychological distinction between the City of God and the City of Man. “In one city,” Augustine wrote, “love of God has been given first place; in the other love of self.” Different loves are ordered to different goods. “For the City of God,” writes Forster, “the only ultimate good is God; other things are good only to the extent that they look to God. For the City of Man, the satisfaction of one’s own desires…is good. And since you cannot satisfy your desires without having the power to satisfy them, the ultimate good for the City of Man, what it desires above all other things, is power.”

 

Through City of God, Augustine argues against early medieval pagans who blamed Christians for the sack of Rome, its loss of earthly power. Augustine saw things differently, however. He saw the sack of Rome as a just punishment of Rome’s depredations. “Remove justice,” he wrote, “and what are kingdoms but gangs of criminals on a large scale? What are criminal gangs but petty kingdoms?” While the City of Man desires power; the City of God desires justice.

 

The different goods sought by different loves does not mean that there can be no social cooperation between the two cities, however. “Just as there is no man who does not wish for joy,” Augustine writes, “so there is no man who does not wish for peace.” The cities cannot agree on eternal goods, but they can achieve compromise on temporal goods. Writes Augustine: “Thus even the Heavenly City in her pilgrimage her on earth makes use of the earthly peace, and defends and seeks the compromise between human wills in respect of the provisions relevant to the mortal nature of man, so far as may be permitted without detriment to true religion and piety.”

 

Justice leading to peace is the leitmotif of Augustine’s political thought. But how do we define justice and peace between the two cities when neither the Old or New Testaments are clearly applicable? Through natural-law reasoning. In Chapter 4, Forster names natural law “the most important political idea in history.” Natural law “holds that the only proper basis of political authority is the moral laws pertaining to life in the present world (do not kill, do not steal, keep your promises, help those in need, preserve the community, etc.) rather than laws pertaining to eternal matters.” Natural-law reasoning was “the driving force behind most…Christian political thought for as long as Christianity has existed.” But it was only in the Middle Ages that Christian thinkers (especially Aquinas and Ockham) produced “a fully developed understanding of natural law and its implications.”

 

Forster outlines six “basic principles of natural-law thought”:

 

 

Of course, medieval society had a degree of unity that is no longer present in society. Yes, the various kingdoms battled one another, but they did so under the aegis of the Roman Catholic Church, whose doctrine established a unifying and authoritative worldview for the combatants.

 

The Protestant Reformation, the subject of Chapter 5, shattered that unity and gave rise to the nation-state, which is the basic political unit of modern society. Interestingly, the Reformers—at least the Magisterial Reformers—did not repudiate natural-law reasoning. What they repudiated was the authority of the Catholic Church, which provided the social glue to medieval society. In place of one church, the Protestant Reformation ushered in an era of multiple, conflicting spiritual authorities under the doctrine of cuius regio, eius religio (literally, “Whose realm, his religion). Predictably, war ensued.

 

Chapter 6 takes up the emergence of religious freedom in the Enlightenment, citing John Locke as a pivotal figure. The medieval and Reformation churches (magisterial Reformation, not Anabaptist, that is) seem to have forgotten the lessons of the early church and Augustine. Both realized that believers and unbelievers could cooperate and through the state realize temporal goods. Both also wanted the state to stay out of eternal affairs. By contrast, the medieval and Reformation churches used the state to enforce religion, thus sacrificing peace. In his Letter Concerning Toleration, Locke wrote: “The commonwealth seems to me to be a society of men constituted only for the procuring, preserving, and advancing their own civil interests.” Those civil interests did not include enforcement of religion. “The care of souls cannot belong to the civil magistrate because his power consists only in outward force, but true and saving religion consists in the inward persuasion of the mind, without which nothing can be acceptable to God.” Forster does a good job of showing that Locke’s conclusions were based not merely on natural-law reasoning, but also on a close consideration of what the New Testament teaches about faith. Since the New Testament does not teach the civil enforcement of religion, Locke could find no use for it either.

 

While Chapter 6 focuses on Locke’s Letter Concerning Toleration, Chapter 7 focuses on how the American Founders used the natural-law reasoning of his Two Treatises of Government to justify revolution. Now, the pro-revolutionary stance of many American Christians is striking. The New Testament commands obedience to government (Romans 13), and the government in power at that time was both unjust and persecutory. How then can a Christian countenance revolution?

 

Locke turned to natural-law reasoning. Remember, natural law authorizes societies to set up governments, and the purpose of those governments is to practice justice leading to peace. If those governments practice injustice, however, who enforces justice against them? Society as a whole. Here we see that government arises, in the words of the Declaration of Independence, from “the consent of the governed.”

 

Perhaps you think that it is not the Christian’s duty to enforce justice against government. After all, Romans 13 does command obedience. But remember the immediate context in which Locke is writing. England has endured decades of civil strife resulting from religious strife, as Protestant and Catholic claimants to the throne struggled for possession of it. In such a situation, Christians were forced to make a choice as to who was the legitimate political authority to be obeyed. The mere possession of superior power could not settle the issue, since possession switched sides frequently. What had to be decided was the justice of the claims. In other words, who had the right to rule. But since an unjust government had no right to rule, it could be overthrown by revolution. That is what natural-law reasoning, at least in Locke’s hands, seemed to require.

 

The trend of natural-law thinking, then, at least as it developed in England and America, was toward liberal democracy, in which political authority rests on the consent of the governed. But liberal democracy had its critics, both externally and internally. This is the focus of Chapter 8. Externally, the greatest critics of liberal democracy in the twentieth century totalitarian Communism and Nazism. Internally, theologians such as Karl Barth and Reinhold Niebuhr questioned its natural-law foundations, whether in toto (Barth) or in ironic part (Niebuhr). Interestingly, C.S. Lewis restated and defended natural-law reasoning in a variety of works.

 

On the whole, I think Forster’s book is a fair-minded summary of the development of Christian political thought, whose dominant mode is natural-law reasoning. I also think he correctly notes how natural-law thinking has historically tended to underwrite the project of liberal democracy. I was especially impressed with his two-chapter treatment of John Locke, which I have oversimplified (but I hope not distorted). Forster does not ask argue that natural-law reasoning is right. His literary enterprise is historical and analytical, rather than normative and apologetic. Nonetheless, I get the feeling that Forster himself believes the basic evolution of natural-law reasoning he outlines to be essentially correct.

 

It is a sign of his fair-mindedness, however, that he admits the triumph of religious freedom and liberal democracy is not without problems. Specifically, he mentions “the problem of public virtue”: “how do we maintain political adherence to the moral laws necessary for politics (do not kill, do not steal, keep your promises, etc.) without a shared community religion?” In our deeply divided, red-state/blue-state country, this is an urgent question without an obvious answer.