But if liberals need to come to terms with these failures, religious conservatives should not be smug about them. The defining idea of liberal Christianity — that faith should spur social reform as well as personal conversion — has been an immensely positive force in our national life. No one should wish for its extinction, or for a world where Christianity becomes the exclusive property of the political right.

What should be wished for, instead, is that liberal Christianity recovers a religious reason for its own existence. As the liberal Protestant scholar Gary Dorrien has pointed out, the Christianity that animated causes such as the Social Gospel and the civil rights movement was much more dogmatic than present-day liberal faith. Its leaders had a “deep grounding in Bible study, family devotions, personal prayer and worship.” They argued for progressive reform in the context of “a personal transcendent God … the divinity of Christ, the need of personal redemption and the importance of Christian missions.”