Of all the social causes that could have plucked latter-day Arthur Ashes and Muhammad Alis from the banally swooshed-up masses, who would have ranked same-sex marriage near the top of the list, or anywhere in the top 100?

It's one thing for the president and national polls to shift in favor of gay and lesbian weddings. But when two NFL players took to the national stage last week to run a good-cop, bad-cop routine on a state legislator, cultural vertigo ensued.

The last time professional football kicked up such a national storm on this issue, more than 100 players signed a 1999 USA TODAY ad supporting Reggie White after a backlash over his anti-gay jeremiads. "Get ready, America," the ad said, "because we're standing with Reggie to defend America."

Today, Ravens linebacker Brendon Ayanbadejo has flipped that script. He has publicly backed same-sex marriage for almost four years. He blitzes philosophical opponents with kindness, even the Maryland delegate who recently wrote to Ravens owner Steve Bisciotti and asked him to shut down Ayanbadejo's advocacy for a campaign in favor of marital equality. The Ravens said no. Ayanbadejo said he wished the delegate, Emmett C. Burns Jr., would "open his heart" on the issue. In defense of Ayanbadejo, Vikings punter, Chris Kluwe, said a lot of things that cannot be printed here. 

With his devastatingly profane takedown of Burns for Deadspin, Kluwe made collateral damage of notions about athletes' apathy and their attachment to antiquated definitions of masculinity. The bad-cop punter finished off a dismantling begun by Ayanbadejo and Browns linebacker Scott Fujita, who as a New Orleans Saint stumped for same-sex marriage during Super Bowl media sessions, a strict no-fly zone for genuine discourse.

Both Fujita and Ayanbadejo grew up in interracial families, aware that, like same-sex couples today, their parents could not have legally married in this country 50 years ago. Ayanbadejo, 36, has a father from Nigeria and an American mother of Irish descent. He is, he says, African and American, but not exactly African-American. Growing up, he became accustomed to never entirely fitting into one group, always being not white enough or not sufficiently black.

That experience may have helped him overlook the locker-room whispers that followed his initial support for same-sex marriage. 

"The first few years, no one even entertained the conversation," Ayanbadejo said. "There was just snickering and stuff in the background. ... Here in 2012, I've had these intellectual conversations about our different points of view, or our agreeing points of view. And I haven't started any of the conversations. Everyone has come up to me."

About 10 teammates have approached him, he said, some agreeing with him unequivocally, others certain that the Bible prohibits homosexuality, but open to the belief that the law must treat all couples equally.

"Not a single teammate has said, 'Hey this is wrong, same-sex couples should not have the same rights as heterosexual couples,'" he said. "That really tells me that there has been a changing of the guard. ... You can't lump us into this big group of homophobic men, because that's not what we are anymore."

In the NFL, where the average career lasts around four years, generational shifts can occur quickly, and Ayanbadejo believes that his younger teammates swayed the tone of the discussion. That demographic analysis underestimates his own influence.

When a rookie arrives in the NFL, he looks for cues from his elders, and usually finds the social guidelines wrapped in cobwebs. The coaches want all deep thought applied to the playbook. Reporters expect no deep thought at all; they're happy to get a quote with just a hint of wit. Agents save their energy to counteract clients' foolish whims, if they dare.

The presence of a 36-year-old, three-time Pro Bowler with alternative views can carry a lot of weight. Ayanbadejo's confident refusal to submit to a decrepit locker-room culture or blowhard politician was bound to win over younger men trained to respect any show of strength. 

Ayanbadejo has always had a reformer's bent. In 2009, the same year he wrote a Huffington Post article in favor of gay marriage, he joined six other NFL players at a rally on Capitol Hill for the FIT Kids Act, promoting fitness and better nutrition in schools. Currently working on his MBA, Ayanbadejo hopes to become an athletic director someday. 

"I pretty much want to revolutionize the way that student-athletes are treated," he said, "and focus a lot more in school and programs after school. If they can make it as professional athletes, that's great. But most of them won't, and I want them to be job-ready in other professions."

The fight for marriage equality taps deeply into Ayanbadejo's personal history, as it does for many supporters. 

The linebacker spent critical adolescent years living in a building designated for LGBT students at the University of California at Santa Cruz. His stepfather worked as the resident director, and the family lived in an apartment at the base of the dorm.

"It was sort of their safe haven, where the students could be themselves," Ayanbadejo said. "I was in eighth or ninth grade, and we'd do these activities with everyone, skits or plays with me and my brother and sister. Men would be holding hands with each other, and women with women, and I was so young I didn't really think much of it. Now, I kind of rejoice when I see same-sex couples together, sharing their love, and being able to be themselves outside, not just in their homes."

Ayanbadejo finds himself evermore passionate about the cause, for both personal and political reasons. Maryland is one of four states voting on a same-sex-marriage ballot measure this fall, making his support vital. 

Thinking about the futures of his two children -- a 6-year-old daughter, Anaya, and 18-month-old son, Amadeus -- also pushed him further into the fray, he said. 

He considered what he and their mom, Natalee, wanted for them, and knew it wasn't a world of restrictive, cold expectations.

They named their son after Mozart, he said, because "I didn't want him to feel pressure to be a football player and fill my shoes. We started looking for an artsy name, so maybe he'll think about being a musician."

He also thought more about the advantages straight couples enjoy that are denied to other people equally in love. His sister, he said, met a man while studying overseas and married him. She could bring him back to the States with legal residency and a chance for citizenship. A same-sex couple would have to separate or go into exile in a friendlier country. U.S. immigration law recognizes only straight marriages.

He also considered Natalee's upbringing, the uncle she lost to AIDS, the way her Latino relatives value their family connections too deeply to shun gay or lesbian members and keep them in the closet.

"So now I'll take a break from dinner and take time away from the kids to reach out while this is a hot-button issue, and talk to as much media and as many people as I can," he said during his seventh interview of his lone day off this week. "I could have done more before. I was in, but I wasn't all the way in. Now, I'm fully vested. I am all the way in."

The transformation of the culture is certainly not complete. Ayanbadejo concedes that homophobic slurs have not been excised from the locker-room vocabulary. 

"I'd say in the past, it would be multiple times a day, and now it's a weekly occurrence," Ayanbadejo said. "And when I hear that, I just say: "You know, you guys, those words aren't fair. And they go, 'Oh I didn't mean it like that.' Well, if you didn't mean it like that, you shouldn't say it. It's like using the N-word in the past."

One has to wonder whether teammates are especially careful around Ayanbadejo. The once-weekly estimate seems extraordinarily low.  

But attitudes are changing so quickly, it's hard to keep up. The dumb-jock image may live on in other incarnations, but, thanks to people like Ayanbadejo, the homophobic version appears to be terminally ill.