Jeff Lowder accused Mark Driscoll of "mind-reading" when he said that Obama is not a Christian, and Steve Hays replied that we have good reason to deny that he is a Christian given his some of his social views and his sympathy with black liberation theology.
A little biblical exegesis might put this in perspective.
Trouble here is that the word "Christian" appears in the Bible as something that the followers of Christ were called by others. It appears, as best I can recall, twice in the whole Bible. It was actually a dirty name, associated with persecution. Acts 11:46 says "and when he found him, he brought him to Antioch. So for a whole year Barnabas and Saul met with the church and taught great numbers of people. The disciples were called Christians first at Antioch." I Peter 4:16 says "However, if you suffer as a Christian, do not be ashamed, but praise God that you bear that name."
In other words he's telling the followers of Christ to praise God for bearing a name given to them by persecutors. Later Christians accepted the name. That's one of the reasons why I find endless discussions about who is, and is not a "real" Christian rather boring. I am inclined to think that acceptance of certain central doctrinal tenets of Christianity are more important that social/political issues, because these involve not merely what is right or wrong, but also what the state should do about it. And since the New Testament was written during a time when Christians had no political power, all it says about the state is to render unto Caesar the things that are Caesar's.
Now, if you're a Catholic, you have a Church mechanism for determining who is a Catholic, and if you part of a church that has a doctrinal confession, you can decide that some people don't belong in your church because they publicly deny central elements of your doctrinal confession. Catholics do say they are the one true church, but they don't deny that those outside aren't Christians, while other churches don't even make the claim that they are the one true church.
On the other hand, Richard Dawkins says that Obama is probably really an atheist, since he is such a sensible person. But I think Jeff would have to accuse him of mind-reading as well. (Interesting point of agreement between Driscoll/Hays and Richard Dawkins).