Question: How could the mother of Jesus have been conceived without original sin? Were not His death and resurrection necessary before anyone could be freed from the sin of Adam? Wasn't the Immaculate Conception an invention of Pius IX; an attempt to restore the prestigue of the Papacy in the secular world?
Answer: God was capable of creating Adam and Eve in the state of "original justice," which is the same as saying "free from original sin." While God is certainly not arbitrary, He abundantly capable of managing His creation as He sees fit. His angel Gabriel informs us that He created Mary "full of grace," even before she gave her consent to become the mother of our Redeemer.1 The collect of the feast suggests that at conception, Mary was allowed to benefit in advance from the foreseen Redemption of her Son. Mary is the "new Eve," created like the old Eve in the state of grace. God planned it that way so that His Son might have an appropriately sinless Mother. It was one thing to be born into poverty, but entirely another thing to be born into sin. The Immaculate Conception was God's prerogative and He exercised it.
Any discussion about the Immaculate Conception that took place before the pronouncement of Blessed Pope Pius IX had to do with the exact moment in which Mary became "full of grace." All of the debates were phrased in terms of "at conception" or "at some instant thereafter." It is difficult to see Blessed Pope Pius defining the dogma in order to enhance his own prestige. Personally he was a man of high birth who strove to live humbly. Publicly, the definition of dogma always find objectors who will be less happy with the Papacy than before.
1. Cf. Luke i: 26-38.