The most misunderstood voting bloc in the 2012 election is the Catholic vote.

Why?

Because there isn’t one.

The religious assemblage, which has evolved over the past century from a strong Democratic constituency into a national election bellwether, is no longer discernible from most other voter groups. As the community has become less homogenous and more assimilated into mainstream culture, so has its voting habits – sending many politicians on a fool’s errand in pursuit of the “Catholic vote.”

“I think the Catholic vote is very fractured right now,” said Rev. Drew Christiansen, S.J., the editor in chief of “America,” a Catholic newsweekly published by the Jesuits.

The breakdown of the Catholic vote in recent presidential elections has been predictive of the ultimate winner, leading many casual observers to label it as a “bellwether” bloc.

President George W. Bush won the Catholic vote, 52 percent to 47 percent, in his 2004 re-election effort, according to exit polls from that cycle. President Barack Obama won the group (which made up 27 percent of the electorate, according to exit polling), 54 percent to 45 percent, during his bid for the White House in 2008.

But to call the Catholic vote a pure bellwether would be a mistake; the determination of an individual’s vote is more likely in 2012 to turn on more common political variables (like income, education, or ethnicity) – than simple religious identity.

“Catholicism was never as monolithic as its foes assumed,” said William Dinges, a professor of religion and culture at the Catholic University of America. “In many respects, Catholics are less distinguishable than they once were from other religious groups.”

A Gallup poll released earlier this month bore out those details.

First Read: Catholic heavyweights challenge Obama rule on contraception

While the survey found Obama and Romney tied, at 46 percent, among American Catholics, support for either candidate broke down along more familiar dividing lines. Obama led heavily, for instance, among Hispanic Catholics, and Romney led (more modestly) among Caucasian Catholics.

Similarly, Romney leads among moderately or very religious Catholics, according to Gallup, while Obama wins Catholics who describe themselves as not especially religious. Highlighting further splits within the Catholic vote along lines of church attendance.

“You want to think about Catholic voters in terms of intensity of their religion,” said R.R. Reno, the editor of the conservative religious journal “First Things.”

“Catholicism tends to be a cultural-ethnic identity ... It makes it very complicated as to how to think about the Catholic vote.”

That hasn't stopped politicians from targeting the "Catholic vote," however. Republicans were vocal critics of Obama’s proposed rule requiring employers to include coverage of contraception in their health insurance plans.

This, in particular, invoked the regulation's effect on employers affiliated with the Catholic Church.

During a February campaign stop, Romney called the proposal a “real blow” to American Catholics. "This kind of assault on religion will end if I’m president of the United States," he vowed.

That issue re-emerged on Monday, when the University of Notre Dame and the Archdiocese of Washington, D.C., joined other religiously-affiliated institutions in filing a lawsuit against contraceptive coverage mandates.

Republicans haven’t been immune from Catholic criticism, either. Many congressional offices pointed to a letter issued by the U.S. Conference of Catholic Bishops, the official voice of the church in the U.S., for its censure of cuts to social programs contained within the 2013 budget authored by Wisconsin Republican Rep. Paul Ryan, himself a Catholic.

“It just strikes me as more problematic for a politician to think in terms of the ‘Catholic vote,’” Dinges said.

Catholics no longer show any overwhelming loyalty to a candidate sharing their faith, at least judging by this year's Republican primary. The Catholic vote made up about a third of the electorate in three of this spring's most competitive primaries – Florida, Michigan and Ohio.

Two Catholics were on the ballot in each of those contests: Rick Santorum, a vocal proponent of the church's teachings on abortion and contraception, and Newt Gingrich, a convert to the faith who frequently screened his film on the late Pope John Paul II on the campaign trail. And yet, Mitt Romney, the former Massachusetts governor who is an active member of the Mormon Church, won the Catholic vote in each of those contests. Gingrich and Santorum had stronger showings among other Christians, especially evangelical voters.

To the extent that any political leader could court a segment of the Catholic vote in future elections, they might only succeed at the margins, or in very specific locations or instances.

“There's a group in the middle, maybe 10 percent, and that's a big enough group in important states like Pennsylvania and Ohio,” said Reese, not coincidentally naming two swing states this fall. “They're extremely important, and the swing voters are what we used to call Reagan Democrats – white, ethnic people who sometimes vote their pocketbook, or sometimes vote other issues.”

Reno, of “First Things,” was also more sanguine about the way higher-intensity Catholics might shift over time. Citing the example of the contraception mandate, he argued that, if the Democratic Party is increasingly seen as hostile to persons of faith, enough Catholics could shift toward Republicans in a way that makes a difference.

“If there's a shift of 10 percent in the way Catholics vote over a 10-year period,  that could be very important,” he said.