>>1660
Tell us how it works, then.
Catechism 493:
>By the grace of God Mary remained free of every personal sin her whole life long.
Ineffabilis Deus of 8 December, 1854
>in the first instance of her conception, by a singular privilege and grace granted by God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved exempt from all stain of original sin.
So she was without personal or original sin "in view of the merits of Jesus Christ"
Is the relevant merit of Christ that needed Mary to be without sin not Jesus' sinlessness?