After the slayings of nine people at a historic African American church in Charleston, S.C., last week, many Republican politicians were quick to characterize it as an assault on religious liberty. But they were a little slower to invoke racism -- a motive that quickly became apparent as we all dug into shooting suspect Dylann Roof's increasingly long paper trail of white supremacism.

But looking at the chart below, it's pretty clear that many Americans -- and especially Republicans -- might have had a similar initial reaction.

The Public Religion Research Institute study shows about half of Americans say that "discrimination against Christians has become as big a problem as discrimination against other groups."

About one-quarter (24 percent) of Americans say they "completely agree" with this statement, while another quarter (25 percent) say they mostly agree.

The results were pretty partisan, too, with 65 percent of Republicans, but only 34 percent of Democrats, saying they agreed with that statement.

And just to reinforce, the question was not whether Christians face any discrimination at all; it's whether the discrimination they face is as big a problem as the discrimination faced by other groups. Those other groups, logic follows, would include African Americans and others that throughout history have faced well-documented and long-running forms of overt discrimination.

Of course, tragedies like the one in Charleston don't happen in a vacuum. And it was hard to escape the likely racial motivations of a white man walking into the historic Emanuel African Methodist Episcopal Church and shooting dead nine people.

But it's also clear that about half of Americans see the predominant religion in the United States -- a religion claimed by more than 70 percent of people in this country -- as facing real discrimination comparable to that faced by, ostensibly, African Americans and others.