By the 1940, the previous interpretation of St. Thomas was challenged. Henri de Lubac led the Ressourcement, " the going back to the sources movement." These theologians read prior texts in a fresh light, and rethought prior interpretations, especially those of human nature towards union with God. By the way, theologians most often focused on the Church Fathers, St. Thomas, and the other Doctors.
de Lubac argued that prior theologians didn't present Thomas Aquinas correctly. In his view, Thomas argued pure human nature did desire union with God and that nothing else, at a minimum, would satisfy it (see the last post!).
So why did this get all nutty? Well, theologians became concerned for the doctrine of "gratuity of grace," that is that grace is freely given. It's in the Scriptures as such; this is the point about grace St. Paul makes most. If God gives us something as part of nature, it would be unjust to withhold that union, and then it wouldn't be a free, unmerited, and unowed gift anymore. These theologians were correct to protect the gratuity of grace, in a way. It's possible to slip into semi-Pelagianism.
But Henri de Lubac argued Cajetan and Garrigou-Lagrange's positions, among other theological opinions, weren't even necessary to safeguard the gratuity of grace.
Grace is an expression of God's love, and by definition it's free and unmerited. Also, God wills to offer union with Himself, and then gives the mechanism to make it happen, i.e. giving us that desire. To say it is the other way creates the issue of justice and is incorrect.
de Lubac's response is to be continued...