As the best-selling megapastor of one of the country's biggest megachurches, Rick Warren, 55, has decried Evangelicals' incursions into the political arena; and yet there he was last August, quizzing both presidential candidates. He has called issues like abortion, stem-cell research and euthanasia "nonnegotiable," while he has pursued his fight against AIDS and poverty. This ideological evanescence ensured that the left would be furious when Barack Obama asked Warren to offer the invocation at his Inauguration — and that the right would be furious when Warren accepted. But in the middle are thousands of pastors whom Warren trains and millions of seekers who follow his every word. Which means he is right where he wants to be.