Why Proportionalism's argument for "reducing abortions" is wrong

This is a follow up to an anonymous commenter that posed that making or keeping abortion legal is good(morally speaking) if it reduces the number of abortions.  This is great explanation why it is an idea that is not compatible with Catholic thought.

Before launching into Aquinas' account of human action that proves so fatal to Proportionalism, one must first understand the substance of the teachings of Proportionalism. Veritatis Splendor sums up the error nicely: "[Proportionalism], while acknowledging that moral values are indicated by reason and by Revelation, maintain[s] that it is never possible to formulate an absolute prohibition of particular kinds of behavior which would be in conflict, in every circumstance and in every culture, with those values."1 Given the fact that the Ten Commandments, among other teachings, seem very absolute, one would think that it is difficult to hold such a view. The Pope explains the way in which the Proportionalists endeavor to bypass such a fundamental barricade: "The criteria for evaluating the moral rightness of an action are drawn from the weighing of the non-moral or pre-moral goods to be gained and the corresponding non-moral or pre-moral values to be respected. For some, concrete behavior would be right or wrong according as whether or not it is capable of producing a better state of affairs for all concerned."2

It is precisely because of the conclusion that there are no universal, morally absolute, intrinsically evil acts that the Church entirely rejects the Proportionalist view. Though the Proportionalists may be acting out of good intentions, the Church cannot in any way make allowances for their teachings. The Pope understands that Proportionalism is an attempt to "provide liberation from the constraints of a voluntaristic and arbitrary morality of obligation which would ultimately be dehumanizing,"6 for, without any real choice, a person is not using his reason and freedom of choice, which distinguish him from the animals. But Proportionalism is one of the "false solutions, linked in particular to an inadequate understanding of the object of moral action."7 Circumstances and intention can play a very important role in moral action, but they "can never transform an act intrinsically evil by virtue of its object into an act 'subjectively' good or defensible as a choice."8 As was said before, Pope John Paul II does not delve into the question of circumstances and intent; for that, one must turn to St. Thomas Aquinas.

The whole article by Marissa Johannes is excellent in explaining the fallacy of Proportionalism.  I highly recommend reading the whole thing. 
http://www.aboutcatholics.com/life_in_christ/proportionalism/

This is what the Jesuits who corrupted Ted Kennedy failed to realize.