The religious identities of Hispanics are also changing, with 69 percent saying they grew up Catholic, but only 53 percent saying they identify as Catholic now. Those saying they are evangelical Protestants have increased by six percentage points to 13 percent. But Hispanics, like Americans as a whole, are increasingly claiming no religion at all: 7 percent of Hispanics say they were raised in a faith but now have no religious affiliation, bringing the total percentage of Hispanics with no religion to 12 percent.

Robert P. Jones, the chief executive of the institute, said in an interview: “If these trends continue, what we’ll see is a growing polarization among Hispanics, anchored on one end by evangelicals, who tend to be conservative, and on the other end by religiously unaffiliated Hispanics. The unaffiliated voted for Obama by 80 percent, so you see really different political profiles.”

Conservatives have often claimed that Hispanics are a natural constituency for the Republican Party because they care about what the party considers family values. This holds true on abortion, with 52 percent saying abortion should be illegal in all or most cases, and 47 percent saying it should be legal. But on same-sex marriage, 55 percent of Hispanics favor allowing gay and lesbian couples to marry, compared with 43 percent who are opposed.

And Hispanics in the poll said they were far more likely to vote for candidates based on their stances on immigration than on their stance on abortion or gay marriage.