Over the last two years, I have found increasing numbers of conservatives deeply concerned by U.S. military intervention in Iraq. They voted for and admire President Bush, but were profoundly disturbed by his second inaugural address pledging to spread democracy worldwide. Now, there is an important new book that eloquently puts in perspective their alarms about America's course in the post-Cold War world. Sands of Empire by Robert W. Merry, a respected Washington journalist, warns of the United States as the ''Crusader State'' transporting American exceptionalism around the world. The book, to be published this month, contends this crusade threatens...