While we’re on the subject of Catholics, here’s some late breaking data from our new American Religious Identification Survey–ARIS 2008. Since the 2001 ARIS, the gap between Catholics who prefer Democrats and those who prefer Republicans has nearly doubled, from eight to 15 points. Overall, Catholics are essentially tracking national trends, just a few points more on the Democratic side.
Actually, there are three data points available, beginning with the 1990 National Survey of Religious Identity (NSRI). All three surveys are based on very large samples–120,000 for NSRI, 60,000 for ARIS 2001, and ARIS 2008 still in the field at 42,000 and counting. So here’s the way it looks over the three surveys:

For all adults, it’s Republicans 30-31-25; Democrats 34-31-34.
For adult Catholics, it’s Republicans 27-28-24; Democrats 38-36-39.

Essentially what’s happened over the past 18 years is that the Republican brand, which was slightly enhanced during the 1990s, has taken a hit, while the Democratic brand, which took a hit in the 1990s, has recovered. The proportion of independents has remained just about constant throughout the entire period, at 30 percent for all adults and slightly less for adult Catholics. There has been an increase over the past seven years in the number of respondents saying they don’t know what they are–9 percent of Catholics and 11 percent of all adults. It is fair to assume that many of these new “don’t knows” are former Republicans trying to figure out what they are. Wherever they end up it’s important to recognize that, contrary to the argument made by Michael Sean Winters in his recent book, Left at the Altar, the Democrats have not lost the Catholics but, to the contrary, are more than holding their own.