Here are three levels of anti-Pelagianism:
- No fallen human being can attain personal union (i.e., union of the relevant sort—such as the beatific vision) with God by his own powers.
- No mere human being can attain personal union with God by his own powers.
- No mere creature can attain personal union with God by his own powers.
An interesting difference at least of emphasis between Catholics and Protestants is that Protestants see Pelagianism primarily as a denial of (1), and focus on (1) in anti-Pelagian polemic, while Catholicism, I think, has an emphasis not just on (1), but also on (2)—grace is not only needed now for fallen man, but Adam and Eve needed grace, too, to attain the beatific vision. And even (3) is probably pretty common in Catholicism. E.g., Aquinas would surely endorse (3). His view of the fall of Satan, if my shaky memory serves me, was that Satan wanted to get by his own powers the good that God was going to give to him by grace—i.e., that Satan was a practical Pelagian.