Aquinas and Trent: Part 3

I've come to believe that a Protestant cannot truly understand why he is a Protestant instead of a Catholic, until he understands why (or whether) he disagrees with the Council of Trent. And he cannot understand why (or whether) he disagrees with the Council of Trent, until he understands the theological rationale behind the teaching of the Council of Trent. And he cannot understand the theological rationale behind the teaching of the Council of Trent until he understands the theology of St. Thomas Aquinas. Therefore, it follows that a Protestant cannot truly understand why he is a Protestant instead of a Catholic until he understands the theology of St. Thomas Aquinas. With that in mind, and with an aim to help reconcile Protestants and Catholics in full communion, I have begun a series of posts titled "Aquinas and Trent" in which I set out to explain Sessions 5 and 6 of the Council of Trent in light of the teaching of St. Thomas Aquinas on the subjects of sin, Christ's Passion, baptism, and justification. Part 3, in which I examine and explain St. Thomas' teaching on the corruption of human nature as an effect of sin is now posted here.