Even after a politically stormy summer, white evangelical support for Donald Trump has remained strong.

Trump’s standing among white evangelicals has remained virtually unchanged at 71 percent, according to a recent Public Religion Research Institute (PRRI) poll conducted in late August and early September.

The results follow a summer marked by crisis after crisis, from Trump’s controversial unpopular directive to separate migrant families to his controversial meeting with Russian President Vladimir Putin to the defection of Trump’s longtime lawyer and fixer, Michael Cohen, who now says Trump ordered an illegal payoff to Stormy Daniels, the porn actress who claims to have had an affair with Donald Trump.

In April, 75 percent of white evangelicals told PRRI they viewed his presidency favorably, an all-time high since the inauguration. Eighty-one percent of white evangelicals voted for Trump in the 2016 presidential election.

White evangelicals remain the only religious group in America to view Trump favorably according to the poll. While white mainline Protestants — which include historically progressive denominations like Episcopalians and Presbyterians — remain about evenly split over Trump, other religious demographics overwhelmingly say they view his presidency negatively. Fifty-nine percent of Catholics and a full 75 percent of black Protestants view Trump negatively, as do 65 percent of the religiously unaffiliated.

What all these numbers suggest is that Trump’s actions — positive or negative — will continue to have very little effect on the opinions of actual voters. In particular, there appears to be very little Trump can do to alienate his white evangelical base, who have continued to support him en masse.

Even this summer’s family separation crisis — during which several prominent evangelical leaders, including the usually pro-Trump Franklin Graham, spoke forcefully against Trump’s family separation policy — seems to have done little to ameliorate Trump’s base’s affection for him.

In fact, PRRI CEO Robert Jones told me, religious groups have remained remarkably consistent when it comes to their stance on Trump throughout his administration. “You might think with as many different revelations and controversies coming out of this administration, there might be some great shuffling of the board, but ... the support or opposition to Trump among religious groups has remained largely steady since the inauguration.”

White mainline Protestants are the only group with a significant shift away from Trump

Jones told Vox that religious and ethnic identity have been reliable predictors of political partisanship since Ronald Reagan’s presidency. “Since Reagan, the basic religious landscape has been very consistent,” he said. White Christian groups — evangelicals, mainline Protestants, and Catholics — have tended to support the Republican candidate, while black Protestants, Hispanic Catholics, the religiously unaffiliated, and other ethno-religious groups lean Democratic.

However, Jones says, we’re seeing a shift away from Trump in one religious demographic: white mainline Protestants, among the most centrist voters. Historically progressive, white mainline voters have tended to vote for Republican candidates by a slight majority. Since Trump’s inauguration, however, white mainline Protestant support for Trump has dropped by a full 9 points, to 48 percent.

It’s unclear, however, how politically significant this shift will be. White mainline churches are emptying at an astonishing rate. In a piece for Vox last year, Lyman Stone argued that this decline, in turn, opened up the metaphorical playing field for adrift voters to be swept up into more extreme political movements, wondering whether “without the common moral language of liberal Protestantism to steer these voters away from demagogues on the left or the right, might they not drift into more extreme political positions?”

Yet, as other religious identity groups solidify their political positions over Trump, it’s worth keeping an eye on white mainline Protestants. They may be the only religious “swing voters.”