http://cara.georgetown.edu/pr061808.pdf

Only 21% of Catholics are either strongly or weakly affiliated as a
Republican. This is the lowest number of Catholic Republicans in a long
time, even going back before 2000 when Al Gore won the Catholic vote.
(23% R in ‘06) and (31% R in ‘04).

60% Catholics are D's to 36% Catholics are R's when leaners are
included.

Democrats have an edge of 8 million voter advantage among registered
voters who are Catholics. If Catholics stick to their current party
identification when voting for president, Barack Obama would have a
potential edge over John McCain among Catholics by more than 8 million
(18 million Democrats to 10 million Republicans)

Catholics are also going post-partisan.
19.5 million Catholics who are independents; 41% (pretty much double the
number of Catholic Republicans), A huge increase since 2004 (30%).

Two major issue shifts among Catholics during the Bush administration:
Catholics are more supportive of diplomacy over military overthrow of
governments and the wealthiest in our society should be paying their
fair share. (20 pt. and 13 pt. shifts). (also a small shift in favor
of support for immigrants)

Health Care for all and a Support for working Americans were the highest
issue area agreements among Catholics.

A staggering 78% of Catholics support Health Care for all: Regardless of
cost, the U.S. government should guarantee basic health care for all
citizens

And 82% support workers right to a living wage and the right to form a
Union.

Weekly attenders are still more likely to be Democrats than anything
else. Thirty-four percent of weekly Mass attending Catholics are
Democrats and an additional 19 percent are not affiliated with a party
but lean toward the Democrats (53 percent identifying or leaning as
Democrats). Twenty eight percent of weekly attenders are Republicans and
an additional 17 percent lean toward being a Republican (43 percent
identifying or leaning as Republicans). Thus, among Catholics attending
Mass once a week or more often, Democrats have a 10 percentage point
edge. Only 5 percent of weekly Mass attenders say they are independent,
apolitical, or identify with a third party. Catholics who attend Mass
less than weekly are even more likely to be a Democrat rather than a
Republican.

57% to 40% for D’s among non-Hispanic white Catholics. Thirty-two
percent of non-Hispanic white Catholics are Democrats and an additional
25 percent currently lean towards the Democratic Party (57 percent
identifying or leaning as Democrats). By comparison, 23 percent of
non-Hispanic white Catholics are affiliated with the Republican Party
and 17 percent currently lean Republican (40 percent identifying or
leaning as Republicans).

Catholics are more than 47 million potential voters in the U.S.
electorate. (That is not far off the number of Americans without Health
Insurance.)