Another good historical problem Dr. Ehrman raises is the issue of Quirinius’ census. Quirinius is the governor who is associated with the change-over from Archaleus being removed as the ruler of Judaea to the appointment of a Roman prefect to take over that responsibility. In the time of 6 AD, Quirinius filled this role similar to what Pilate would later. The argument is that we know Quirinius was ruler in 6 AD, but this is too late to represent Jesus’ birth and be the explanation for why Mary and Joseph have come south from Nazareth down into Judaea into Bethlehem. This is certainly correct. Josephus does not give us any indication of an earlier census or anything similar. We do have a historical anomaly here at this point.
When Luke refers to there being a census taking place all over the world by Augustus, it is not an empire-wide census. Augustus instituted a variety of censuses in specific locations moving from place to place as he gradually took the census of the empire. We know this historically. Often, people deal with this issue syntactically and maintain that Luke is saying ‘before Quirinius’ census in 6 AD this move was made and this registration was made’. While this is possible, it seems perhaps a little odd in terms of the wording of the text.
My own solution is that Augustus got organized to take this census and the mechanizations of it took place somewhere between 6 BC and 4 BC. But the census was not actually executed until Quirinius. In other words, the census was taken under Augustus; then Quirinius took the data, put it together, and presented it to Rome. So Rome actually began to make use of it for taxation under Quirinius. An analogy is when a major freeway is built in a city. Sometimes it takes a while between the planning of the freeway, the actual building of the freeway, and the completion of the freeway. For example, the Dallas Central Expressway had a 30 year period between the planning and the completion of the exercise. So my own take is that this census became associated with Quirinius because he is the one that completed it. But he was not the one responsible for starting it. This is one way to deal with the problem.
Another response is that it is possible Luke had this kind of detail incorrect. It is conceivable, and yet that still does not impact the fact that people would know that Jesus was born in Bethlehem or that he had Bethlehemic roots. Certainly with the early church suggesting that Jesus was born in Bethlehem if he actually was not, then these works are written in an early enough time that people would have been likely to have known, and it would have been a problem historically to present it otherwise.