Perhaps the most surprising thing about Barbara Bush’s pro-gay marriage public-service announcement was that longtime friends and acquaintances weren’t that surprised at all.

“She circulates in social New York,” noted one acquaintance on the party circuit, going on to compare her to the former first daughter to her twin sister, Jenna. “She’s shown herself to be interested in that world. Jenna, I think, is a little more in line with her parents, the marriage in Texas, the Today show job. Barbara has always seemed a bit more intellectual, which would lend itself to this sort of thing. I think she has a nuanced sense of the world, she’s part of the East Coast intellectual elite, she went to Yale and hung out in New York City.” And, said the acquaintance: “Yale is obviously one of the least conservative Ivies.”

Still, the news was momentous, largely because it reinforced yet again the idea that gay marriage is perhaps inevitable. After all, if the most famously religious president in modern history can’t convince his own daughter that marriage ought to be between a man and a woman, whom can he rely on to spread the conservative message about “family values”?

It also put back into the news a woman who, with the exception of an episode involving a fake ID and an attempt to buy alcohol as a teenager, has flown mostly under the radar in the last five years.

“She has always been the type of progressive, free-minded thinker Yale is known for,” said C. Brian Smith, a gay Yale alum whom Bush bonded with over Ally McBeal and later took to the White House. (As he later explained it, meeting her to watch the show saved him the trouble of ever having to tell her that his sexual interests lie with men. They’ve since grown apart.)

“She’s a really cool chick,” Smith told The Daily Beast in an interview Tuesday evening. “I would say that for Barbara and the people she hung out with, the thing we shared was that we were thoughtful and kind. That is progressive thinking. When I was coming out of the closet, Yale was the most lovely place to do that and it was because of people like Barbara.”

During Bush’s four years in New Haven, a couple of boozy episodes led to that party girl image, but several other classmates said the reputation was more than a little exaggerated, the result of a biography that was so opaque a couple of fairly innocuous appearances in the tabloids basically created an entire public persona. As one of them put it: “I always thought that was such bullshit. Who in college doesn’t drink? I’m pretty naïve when it comes to drugs, but I never saw her doing them. Do I think she was a party girl any more so than any other girl of that social stature? No. I never saw her out of control…She had her s--- together.”

During a summer vacation, Bush interned at white-hot design firm Proenza Schouler, where she did well and, indeed, seemed to have her s--- together. The company’s two designers, Lazaro Hernandez and Jack McCollough, were known at the time as a couple and were among the first of many gay men in fashion whom Bush would become friendly with.

“Was she liberal?” says a former classmate. “She always seemed that way to me, but I guess...even my Republican friends from Yale are liberal in the way they conduct their social lives.”

• Stephen L. Carter: Egypt Proves Bush RightOne thing Bush didn’t seem terribly interested in, according to classmates from Yale, was Skull & Bones, the famed secret society that helped lead to the creation of the Central Intelligence Agency. “I heard she was asked but turned it down,” said the former classmate. “Was she liberal? She always seemed that way to me, but I guess I had friends who were Republicans and it didn’t really come up, because even my Republican friends from Yale are liberal in the way they conduct their social lives.”

After she got out of school, Bush moved to the West Village and became a fairly regular presence on the social scene, showing up at big events like the Unicef Snowflake Ball and the American Museum of Natural History’s Winter Dance, frequently accompanied by her photogenic friend Maggie Betts, the African-American daughter of Republican donor Roland Betts. Gay men were all around: the writer Derek Blasberg and his boyfriend Lyle Maltz (another Yale classmate); the designers Zac Posen and Prabal Gurung. By all accounts, Bush has lovely relationships with each of them, which may explain why none of them returned press inquiries Tuesday. (In fact, to some, the startling thing may be not that there are so many gay men around Bush but that they’re surprisingly edgy, cool, gay men. Even back at Yale, said yet another classmate, a gay man whose politics couldn’t be further from George W. Bush’s, “she was much cooler than you would have expected.”)

By 2008, Bush had become increasingly focused on charity work; she’d traveled to Africa and worked with AIDS patients. She also set up a foundation called Global Health Corps, to address what she called the “extreme disparity in health outcomes and access to health care that exists today between the world’s rich and the world’s poor.” This put her in touch with both with liberal women’s activists in Third World countries and well-to-do gay men who work in HIV treatment and prevention.

Nevertheless, few people who know Bush think she’s about to become a vocal opponent of other issues important to Republicans, even as she breaks with her father on this one. Said Smith: “She has always been a good friend to her friends, and since she’s always had gay friends, it’s not surprising to me that this is the issue she’s coming out in favor of…there are lots of ways I differ from my father. She loves her dad, she’s a good daughter, but she loves her friends too.”

Jacob Bernstein is a senior reporter at The Daily Beast. He has also written for New York magazine, Paper, and The Huffington Post.