This week's heresy comes to us from the Reformation era, blending bits of Catholicism with Calvin's TULIP principles (and a little bit of Arminianism). For those not familiar with TULIP, it stands for: Total Depravity (or, "Original Sin"), Unconditional Election (or, "no free will"--the Lutheran interpretation of this idea is similar but not quite the same, although we sometimes call it by the same name), Limited Atonement (or, "God predestined some to heaven..."--unless you're a double predestinationist, which adds to the end, "...and the rest to hell"), Irresistible Grace (or "if God 'elected' you to salvation, you have no free will to reject it"), and Perseverance of the Saints (or "once saved, always saved").
Jansenism was a 16th-18th century French Calvinist-flavored movement within the Catholic Church that arose out of the Council of Trent (1545-1563), with emphasis on original sin, human depravity, the need for divine grace (with huge weight placed on efficacious grace) and predestination. They believed that there are some commandments no human could ever keep no matter how hard they tried, and that it was impossible to resist grace. They subscribed to the Semi-Pelagianism teaching that man may both resist and ‘accept’ grace. By Pope Innocent X’s papal bull in 1653, Jansenism was condemned as heretical.