Despite their apparent differences, Bush and Caldwell have a lot in common. Both are Texans. Both are Methodists. Both earned MBAs from renowned business schools. And both have a passion for using faith-based programs to meet social needs.

The two men have been friends ever since Bush (then governor of Texas) learned of Caldwell's community-development efforts. Today, Caldwell occasionally prays with the President over the phone, and Bush has long pointed to Caldwell's work as a positive example of what can be accomplished through local churches and parachurch ministries.

In his hometown of Houston, Kirbyjon Caldwell is known for his lively preaching—he strikes some as equal parts motivational speaker and revivalist. But the real buzz on Caldwell concerns his success in leading his church, Windsor Village United Methodist, into real estate and other economic-development ventures. Exhibit A is the Power Center, a 104,000 square-foot former Kmart that now houses a private Christian school, a branch of Houston Community College, office space for small businesses, a pharmacy, a hair salon, a federal public-assistance office for women and children, and the ...