Evangelical theologian Wayne Grudem was one of Donald Trump’s most surprising endorsers earlier this year, saying that the Republican presidential nominee was “a morally good choice.” Grudem’s endorsement set off a wave of controversy among evangelicals, who have been deeply divided over this election.

Some evangelical leaders who support Trump said they continue to back him, many of them denouncing his recently revealed comments about sexual assault but saying they still see him as the best choice. But Sunday, Grudem, a conservative theologian respected in many evangelical circles, pulled back his support and called for Trump to withdraw. The move could signal a loss of support for Trump from evangelicals, many of whom see him as a better option than Democrat Hillary Clinton.

“There is no morally good presidential candidate in this election,” Grudem wrote. “I previously called Donald Trump a ‘good candidate with flaws’ and a ‘flawed candidate’ but I now regret that I did not more strongly condemn his moral character. I cannot commend Trump’s moral character, and I strongly urge him to withdraw from the election.”