Its claim is that the nativity was was written to compete with the Roman claims of divinity for their Emperors. For example, it quotes:
“The following was found chiseled on the ruins of an old government building in Asia Minor, dated 6 BC:Definitely worth a read.
‘The most divine Caesar . . . we should consider equal to the Beginning of all things . . . for when everything was falling (into disorder) and tending toward dissolution, he restored it once more and gave the whole world a new aura; Caesar . . . the common good Fortune of all . . . The beginning of life and vitality . . . All the cities unanimously adopt the birthday of the divine Caesar as the new beginning of the year . . . Whereas the Providence which has regulated our whole existence . . . has brought our life to the climax of perfection in giving to us (the emperor) Augustus . . .who being sent to us and our descendents as Savior, has put an end to war and has set all things in order; and (whereas,) having become (god) manifest /PHANEIS/, Caesar has fulfilled all the hopes of earlier times . . . the birthday of the god (Augustus) has been for the whole world the beginning of good news /EVANGELION/ concerning him.’” (Shane Claiborne, JESUS FOR PRESIDENT, p 70)