Christianity Today‘s monthly online presidential poll shows Barack Obama leading John McCain for the first time, 51 percent to 41 percent. A month ago, the positions were reversed, with McCain ahead of Obama by 50-33. Online polls are dubious creatures, the product of self-selection and subject to manipulation. Still, given that the total number of votes has increased only slightly since last time (from 3,007 to 3,189), this one may mean something. Such as that mainstream evangelicals of the CT-reading variety are shifting toward Obama.