DETROIT — With a Michigan win all but guaranteeing Donald Trump the White House, his campaign deployed disciples in downtown Detroit last week to boost his backing among black voters.

Pastor Lorenzo Sewell of 180Church, who gave a fiery prime-time speech at last month’s Republican National Convention, emceed the Thursday roundtable, which aimed to route Republican outreach through a trusted source in the community: the black pastor.

Sewell said he has always voted Republican, though few knew — until Trump’s July appearance at his church, which Sewell calls his “coming-out party.”

“My whole life, I’ve had the honor to serve in Detroit, Pontiac and Saginaw,” he said. “Always serving in Democratic strongholds but always voting Republican.”

Why?

“I believe in the Bible.”

A fellow churchman echoed his remarks at the event, held at restaurant Table No. 2.

“I’m often asked why I’m even involved with this whole political madness going on our country right now,” said Apostle Ellis L. Smith, who leads Jubilee City Church in neighboring Redford. “But I’m not politically motivated. I’m really not a Republican, I’m not a Democrat, I’m a Bible-crat.”

“We have to begin to think biblically,” Smith said. “Not culturally, biblically. Not black or white, biblically. As a grandparent, and now I’m a great grandparent, I don’t want little boys who think they’re girls going into the bathroom with my grandchildren.”

“As Detroit goes, so goes America,” Smith added. “And as America goes, so goes the world. So what we do and how we do it has the capacity to change everything.”

Clinton Tarver, 74, knows firsthand what the Trump campaign is up against.

The Clint’s Hotdog Cart and Casual Catering owner is running as a Republican for the Ingham County Commission. He and his wife, Linda, have been involved in GOP politics for years; she’s a former civil-rights commissioner for the state.

When Tarver hits the campaign trail, he has to fend off two foes: general apathy and particular antipathy when people learn he’s a Republican.

“One friend of mine asked for a Trump sign,” Tarver told The Post. “So he could burn it. That’s cold, you know? But it’s the kind of stuff that we go through.”

Tarver hopes to move the Overton window to the point where it’s not a shock for someone to see a black Republican at the door.

“People need to be free to make their own choices,” he said. “We have to give them something to choose.”

Martell Bivings, the black Republican running against Democrat incumbent Shri Thanedar in the congressional district that covers Detroit, was not in attendance. But he has warned the Trump campaign that without a real outreach effort to the African-American community, the black votes Trump hopes for won’t materialize.

“I know those black men. I’m related to those black men,” Bivings told The Post. “They’re not going to go to the polls. They’ll say ‘I ain’t make it to the polls; was Election Day last week?’”

Alexandria Taylor, executive vice chair of the 13th District Republicans, agreed with Bivings on the importance of reaching out and said the pastors’ roundtable was a good start. The campaign is ramping up its outreach efforts every Saturday through Election Day.

So how can Republicans win more of the black vote?

“I think it has to be the ground game, the door knocking,” Taylor said. “I’m someone that spent majority of my adult life in the Democrat Party, and then I switched and came over here, and there are stark differences.”

“The Democrats, to me, take advantage of the black vote. So we can’t do that same thing and expect it to just pop out of thin air,” she continued. “We have to be willing to do the work and have the conversations. There’s no way around the hard work.”

Mike Rogers, Michigan’s Republican Senate candidate, was the only non-pastor with a speaking part.

The former congressman had recently joined Sewell on the east side of Pontiac — “the ‘hood,” Sewell noted — to reach black voters.

He told them what he told the pastors Thursday.

“I’m not asking you to be a Republican,” Rogers said. “I am asking you to take a chance on a set of ideas that will help this community, that will help us all grow.”

While the pastors talked about the many ways America strays from God’s word, including abortion and transgenderism, Rogers focused on literacy.

Illiteracy in the black community is robbing people of their futures, he said.

“We have a literacy crisis in America, and it’s not just in black neighborhoods or Hispanic neighborhoods or white neighborhoods, it’s all of us,” Rogers said. “Eighty percent of Michigan students cannot read at grade level.”

“I think education today may be the biggest civil rights issue of our lifetime,” he added. “If you can’t read by the fourth grade, you have a 70% chance of going to prison or being on welfare.”