But as the mayor of South Bend, Ind., devotes more effort to campaigning for black votes in the South and elsewhere, he will have to break down some resistance over his sexual orientation, particularly among older voters, according to interviews with more than a dozen African American activists, political strategists and clergy, as well as a review of public polling.

Buttigieg and his campaign are well aware of the issue. As he skips from sold-out fundraisers to overflowing rallies around the country, Buttigieg set aside time last week for a smaller gathering of black LGBTQ faith leaders and activists in Houston. Gathered around a glass coffee table, Buttigieg opened up to the group of a dozen about his record with African Americans as mayor in South Bend, Ind. — an area that has generated some criticism — as well as his agenda for black voters and his experience as an openly gay candidate for president, including the challenges he may face.

“He’s white, male and gay, all three of those things are going to create obstacles for various communities — specifically, I think, the white and the gay, for the black community, are definitely going to be obstacles for him,” said Harrison Guy, a Houston-based choreographer and LGBTQ activist who led the discussion with the mayor. “He’s very aware of that.”