At Iowa rallies in the last week before the caucus, some fear the Indiana mayor’s sexuality will make him a risky choice as the Democratic candidate who can beat Trump

Jerry Pinneke is backing Pete Buttigieg for president despite himself. The retired engineer, who worked in the US, Brazil and the UK, likes the Indiana mayor’s youth, is impressed by his ability to speak eight languages, including Norwegian and Dari, and calls him a natural leader. But he has had to set one issue aside.

“I’m a homophobe,” said Pinneke after attending a Buttigieg rally in Ankeny, Iowa, as campaigning in the first vote to select the Democratic presidential candidate heads into the final stretch before the state’s caucus on 3 February. “I get around gay people, that isn’t the world that I grew up in and it bothers me.”

Pinneke, 71, said he will vote for the gay military veteran despite his own prejudice, although he flinches at the thought of a President Buttigieg with his husband, Chasten, as First Gentleman.

“I grapple with that. But so what? Does it hurt anybody? I haven’t seen it. So why is that an issue for me? Is it because I’m an old son-of-a-gun and I didn’t grow up that way? That’s not a good reason not to vote for him,” he said.

But Pinneke is not alone in wondering if others might fail to set their prejudices aside, and whether that makes Buttigieg, a 38-year-old Harvard graduate, Rhodes scholar and former US navy intelligence officer who served in Afghanistan, a risky bet as a presidential candidate.

Facebook Twitter Pinterest Jerry Pinneke. Photograph: Chris McGreal/The Observer

The South Bend mayor has blazed an impressive streak into the Democratic primaries as an unknown from a small midwestern city. When campaigning kicked off last year, the mantle of youthful upstart was held by the Texas congressman Beto O’Rourke, who arrived in Iowa bolstered by nearly snatching Ted Cruz’s seat in the US Senate. But O’Rourke quickly burned out, as voters were turned off by a lack of substance behind the show.

In contrast, Buttigieg’s relentless campaigning won over voters, with his upbeat message, military background and, for some, his religious faith. He positioned himself as a more youthful Joe Biden in favour of incremental change in contrast to the more radical platforms of Elizabeth Warren and Bernie Sanders. His star climbed and so did his poll numbers until, by November, Buttigieg was the frontrunner in Iowa. But since then, he has fallen back, as voters focus on the fraught question of who is the best candidate to beat Trump.

A CNN poll last week showed all four of the leading Iowa candidates beating Trump in the general election, but Buttigieg was ahead by the slimmest margin. In Iowa, he remains very much in contention, within a percentage point of Sanders and Warren. But nationally he trails his main rivals badly.

Debates about electability have flared up periodically in American history. The political establishment questioned if a Catholic could win the White House when John F Kennedy ran in 1960. Barack Obama’s campaign was accompanied by plenty of speculation as to whether the US was ready for its first black president, a question answered decisively by the voters.

This month’s bitter confrontation in a televised debate over what Sanders said to Warren in private about the prospects for a woman to be elected president revived chatter over whether gender is an additional obstacle. Hillary Clinton’s defeat of Donald Trump by nearly 3 million in the popular vote, only to be robbed of the presidency by the vagaries of the electoral college, would say not.

The issue hasn’t entirely been laid to rest. Warren has faced questions from women at her rallies about whether her gender will be a disadvantage, with Trump stalking the debate stage.

Buttigieg’s sexuality is a more awkward question for some Democrats. They do not want to feed prejudice at a time when the US is more tolerant toward the LGBTQ community than ever. Support for same-sex marriage has flipped from two-to-one against 15 years ago to the reverse today. As attitudes have evolved, institutions have followed, from the scrapping of the prohibition on publicly identifying as LGBTQ in the military to the supreme court’s ruling in favour of marriage equality.

But for those calculating who would be the best candidate to get the man they regard as the worst president of modern times out of the White House, there is a nagging fear that Buttigieg’s sexuality could cost him votes if he were the candidate, and let Trump back in.

Only half of American voters said they were ready for a gay president, according to a poll for Politico in October. Just a quarter of voters thought their neighbours would support a LGBTQ president – a statistic that feeds into concerns among some Democratic primary voters that, while they personally have no problem with Buttigieg, others might. That in turn makes voters like Janet Jalbert nervous.

Facebook Twitter Pinterest Janet Jalbert. Photograph: Chris McGreal/The Observer

“I think we would have more trouble right now accepting a gay man and having a First Gentleman in the White House than we would a woman president,” said Jalbert, a post office worker and undecided voter, at a Warren rally. “Between Warren and Buttigieg, I would go with Pete. However, I believe Elizabeth probably has a stronger chance just because of the way the world is right now. Old-school people. And that’s the only thing he has going against him. It’s not his sexuality. It’s people with closed minds.”

Jalbert said the concern that Buttigieg’s sexuality might diminish the anti-Trump vote was enough for her to shy away from supporting him.

“Now, if he were to become vice president, I think that would be a great way to get him in there. And then people could see what it was all about,” she said.

At a Sanders rally the following day, Ashly Moore, an occupational therapist, expressed a similar sentiment. “I like Pete but I do have concerns that he could not be as electable because of who he loves,” she said.

Last July, that concern was reinforced by the findings of a focus group of black Democratic primary voters in South Carolina, questioned for the Buttigieg campaign. He does poorly in the south in general but particularly among African Americans.

“Being gay was a barrier for these voters, particularly for the men who seemed uncomfortable even discussing it,” said the report leaked to the State newspaper in Columbia, South Carolina.

The report said that was not necessarily a red line to voting for him “but their preference is for his sexuality to not be front and center”.

One man told the focus group: “I’ll go ahead and say it. I don’t like the fact that he threw out there that he lives with his husband.” A woman described Buttigieg speaking about Chasten as “too much information”.

Johnnie Cordero, the chair of the black caucus for South Carolina Democrats, told the New York Times that he met Buttigieg to discuss the issue. “To be honest with you, it’s going to be a problem. I know he knows that because we’ve discussed it,” Cordero said. “My advice to him was, don’t flaunt it.”

Still, some supporters of rival candidates do not think it is an issue. At the Warren rally, Dylan Baker said the question of sexuality and electability had come up in family discussions.

“My dad’s a Democrat. He’s leaning to Biden but he also really likes Pete Buttigieg and we were talking about this question of electability and I was saying him being gay will not affect people’s voting. He said: ‘Oh, yeah, I forgot he was gay.’” Baker paused and then added: “But maybe that will affect things. We’re never past those sorts of things.”

Buttigieg has sought to defuse the issue with some black voters who oppose same-sex marriage on religious grounds by drawing parallels between the struggle for gay rights and the challenges facing other minorities. He has also said that once people get to know him they will get over the fact that he is married to a man, an assertion borne out by the focus-group report, which noted that “after seeing the mayor speak, most voters … seemed to be able to get past his sexual orientation”.

Bob Sohm, a Buttigieg supporter at a rally in Sioux City, Iowa, agreed with that. “People have their prejudices but it can be done. We’ve never elected a black president until now. It’s got to start somewhere.

“I think it’s just people need to be more educated about him and know his policies, and maybe think ‘I can start to consider this guy because maybe he can win’.”