Political Myth: Roman Catholics in the United States tend to be pro-life.
Reality: Taken as a whole, Roman Catholics in the United States, as a group, are no more likely to be pro-life than the general population.
In 2009, Gallup published a scientific survey in which it found, among other things, that 40% of Roman Catholics in the United States believe Abortion is “morally acceptable,” as compared with 41% of people who weren’t Roman Catholic. That same survey also asked Roman Catholics and non-Catholics about a variety of other social issues, and found that Roman Catholics were significantly more likely than non-Catholics to find “morally acceptable” that such things as sex between an unmarried man and unmarried woman (67% of Catholics vs. 57% of non-Catholics); Divorce (71% of Catholics vs. 66% of non-Catholics); and homosexuality (54% of Catholics vs. 45% of non-Catholics). Notably, the official doctrine of the Roman Catholic Church itself forbids all three of these things.
Of course, in drawing the types of conclusions about the U.S.’s Roman Catholic population, one inevitably bumps into what is commonly known as the “no true Scotsman” argument. This is the claim that although some people who call themselves “Catholic” may disagree with the Catholic Church’s teachings on such things as abortion, divorce, and fortification, those people aren’t “true Catholics.” This page will not attempt to resolve the question of who is and who isn’t a “true Catholic,” but it is a fair point to mention that there are definite difference between people who self-identify as “Catholic” when it come to how “Catholic” they really are.
Gallup tried to address this issue by comparing Catholics who attend church “regularly” (defined as every week, or almost every week) with those who don’t. The contrast was striking. Among regular Catholic churchgoers, belief in the “moral acceptability” of abortion fell to 24% (vs. 52% of other Catholics) ;sex between an unmaried man and woman fell to 53% (vs. 77% of other Catholics) ; divorce fell to 63% (vs. 77% of other Catholics); and homosexuality 44% (vs. 61% of other Catholics). The survey does not attempt to answer the question of where the causation lies: Do Catholics become more likely to attend church regularly when they agree with the Church’s positions on these social issues, or do Catholics’ beliefs on social issues come into line with those of the Church the more often they attend?
But either way, it would seem that regular church attendance is a far better predictor of one’s position on the moral acceptability of abortion than Catholicism is. Among non-Catholics who attend church regularly, only 19% believe Abortion is morally acceptable (vs. 24% of regular Catholic churchgoers).
Note that the question of whether abortion is “morally acceptable” is quite different from the question of whether abortion should be legal. According to a public opinion poll conducted by Quinnipiac University in 2009, 50% of Catholic voters believed abortion should be legal in “all” or “most” cases, vs 51% of non-Catholics.