Theological hair-splitting aside, keep in mind that not all of the 3% in question has any faith in God--many are liberal secularists whose true house of worship is the ACLU. They're the professionals at making these kinds of divisive political statements. It raises the money and garners the votes, you know.
Keep in mind that most of the "Christians" in the country make no attempt to lead a Christian life. If they go to church, it is because the neighbors expect it, or to make business contacts or for the socializing.
They are nominal Christians because mommy and Daddy are nominal Christians and they haven't enough originality in them to think about religion or what they believe or don't.
SO9
No doubt the same can be said of many who are raised Christian and Muslim, too.