The Public Religion Research Institute released a massive new survey of American religious adherence today. Among other things it contained this stunning insight into the current state of our political parties:

“Today, roughly three-quarters (73%) of the Republican Party is white Christian, but fewer than one-third (29%) of the Democratic Party identifies this way.”

Among Republicans, 35 percent are white evangelical Christians, 18 percent are white members of other Protestant denominations, and 16 percent are white Catholics. Among Democrats those shares are 8 percent, 11 percent and 10 percent, respectively.

Just 7 percent of Republicans are black Protestants, Hispanic Protestants or Hispanic Catholics. By contrast those groups comprise nearly one-third (31 percent) of today's Democratic Party.

From a demographic standpoint, the modern Republican Party looks much like the America of 40 years ago — in 1976, for instance, 81 percent of Americans were white and Christian. Today white Christians account for just 43 percent of the population.

President Trump, who campaigned on a platform of making America great again, capitalized on white Americans' anxieties about these demographic changes in 2016. In September of that year he told Pat Robertson's Christian Broadcasting Network “if we don’t win this election, you’ll never see another Republican and you’ll have a whole different church structure.”

He added “I think this will be the last election that the Republicans have a chance of winning because you’re going to have people flowing across the border, you’re going to have illegal immigrants coming in and they’re going to be legalized and they’re going to be able to vote, and once that all happens you can forget it.”

Previous polling from PRRI showed how these messages resonated with white voters. After the election, fully two-thirds of Trump voters told PRRI the election represented “the last chance to stop America’s decline.”

Pundits have often criticized the Democratic Party as beholden to “identity politics” — seeking voter loyalty based on their characteristics (gender, ethnicity, sexuality) rather than via a coherent set of principles or policies.

But after a 2016 GOP primary in which the winning candidate continually flouted conservative orthodoxy on economics and national security, the party's ethnic and religious uniformity suggests it relies strongly on an “identity politics” of its own — an appeal to white Christians at a time when their status as the nation's overwhelming majority is slipping away.