The Catholic denomination votes democrat and always has, it is a church denomination not a race, and their vote has always been predictable, and democrat, and always will be, with extremely rare exceptions.
The Protestant vote has gone democrat 3 times in history, and the second largest church denomination in America, a Protestant one, is about 80% republican voting.
Even Hispanics become more anti-leftwing when they leave the Catholic denomination for a Protestant one.
You seem to be confusing Catholics with Jewish voters. If it "has always gone Democrat", how the heck did George W. Bush, Ronald Reagan, Richard Nixon, and Dwight Eisenhower WIN the Catholic vote when they were running for President? None of them were Catholic candidates.
That seems to reflect that Catholics vote how the nation as a WHOLE votes (unlike Jewish voters, who reflectively vote Dem, even if a Republican Presidential candidate wins the nation as a whole easily) John Kerry is a Democrat, and he LOST the Catholic vote, despite BEING a Catholic. So what happened to Catholics "always voting Democrat" in those elections?
Most pollsters disagree with your premise that Catholics are a safe Democrat voting bloc. That might have been true in the 1930s, but it certainly isn't true given how Republican Presidential candidates have won Catholics numerous times in recent decades. Jews are a safe Democrat voting bloc that has overwhelmingly supported every Dem Presidential candidate for at least 80+ years (in contrary to numerous Republicans who fantasize about how Jews are "in play" every election cycle), whereas Mormons are a safe GOP voting bloc that reliably votes Republican even when Republicans do poorly nationally (Bob Dole, John McCain, etc.). Catholics are as swing vote that tend to support the candidate that the country as a whole supports, which the occasional exception.
In fact, 2012 was the third straight Presidential election where the Catholic vote has been a near-carbon copy of the overall vote nationwide. If Catholics are "safely Democrat", shouldn't have Obama to win over much more than 50% of them? Shouldn't have John Kerry, a Catholic and a Democrat, won the Catholic vote in 2004 INSTEAD of George W. Bush?
Going by the data in recent decades, if "Catholics vote democrat and always have", then America as a whole must also be "safe and reliably Democrat"
In fact, given the trend of the polls in 2014, I'm betting Republicans win a majority of Catholic vote THIS November. Want to take me up on that one, since you're so sure that Catholics are "predictably always Democrat"? I'd be happy to bet you money.