The Rev. Al Sharpton warned Democrats on Wednesday that Donald Trump is a formidable candidate who poses a serious “threat” to their party’s presidential nominee in November.

“Trump has shown he can drive up turnout in primaries. He’s proven he has a following. He has shown he can bring in new voters,” the activist preacher told The Post.

Sharpton said the challenge for Democrats — meaning likely standard bearer Hillary Clinton — is avoiding a precipitous fall-off in the record black vote that turned out for President Obama in 2008 and 2012.

“The Democrats are going to have to bring out their base — plus,” Sharpton said.

As for supporting Trump himself, Sharpton said that won’t be happening “in this lifetime.”