But, while appearing on Axios on HBO, he demurred on speculating about who, specifically.
“My gaydar doesn’t even work that well in the present, let alone retroactively,” said Buttigieg, 37. “But one can only assume that’s the case.”
The mayor of South Bend, who has transformed from little-known politician to one of the leading contenders for the Democratic presidential nomination, was responding to a question about how he might combat criticism from conservatives that he is too young, too liberal and too gay.
“I’ll respond by explaining where I want to lead this country. People will elect the person who will make the best president,” Buttigieg said. “And we have had excellent presidents who have been young. We have had excellent presidents who have been liberal. I would imagine we’ve probably had excellent presidents who were gay — we just didn’t know which ones.”
Statistics about how many people in America identify as gay, or more broadly as LGBTQ, have ranged over the years.
According to a 2011 report, about 3.5 percent of American adults were estimated to be gay or bisexual while the most recent count from the Movement Advancement Project found approximately 3.3 percent of adults in the U.S. are LGBTQ, or about 11 million people.
However, there are inherent problems in surveying the LGBTQ community, given the discrimination they face and their reluctance to publicly identify themselves. What’s more, not every LGBTQ American agrees on the use of the same set of identifiers, such as gay or queer.
During his Sunday interview on Axios on HBO, Buttigieg said, “Statistically, it’s almost certain” one of the previous 45 presidents was gay. (Elsewhere in the episode, he discussed President Donald Trump‘s handling of the southern border and the Middle East, among other issues.)
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Curiosity and debate about the possibility of a gay former president is nothing new, with much of the discussion centering on James Buchanan and Abraham Lincoln. Both men had emotionally and physically close relationships with men, though whether either experienced same-sex attraction is in dispute.
Buchanan, a one-term president on the eve of the Civil War, was a notorious bachelor. Lincoln had four children with wife Mary Todd Lincoln.
As TIME detailed earlier this week, modern discussions of gender and sexuality are more complicated when applied to historical figures — not because same-sex attraction did not exist throughout history but because descriptions of sexual identity and the customs about same-sex behavior have changed drastically over the centuries.
“If what [Buttigieg’s] remarks were that it’s likely that … someone in the past probably experienced same-sex desire, or same-sex attraction, or same-sex encounters, I would say yeah, I would agree with him,” history professor Rachel Cleves told TIME.
“In some ways, the first half of the 19th century was much more open toward physical touch between men and expressions of love,” Cleves said. “Did James Buchanan or Abraham Lincoln identify as ‘gay’ in the modern sense of the term? That would be very difficult. But did they have longstanding relations with other men? In both cases I think the answer is yes, they had deeply loving and physically intimate — although I don’t know that they were sexual — relationships with other men.”