Denver Broncos second year quarterback Tim Tebow may not actually be Jesus, but he is capable of performing miracles. That’s according to the logic of one of the most captivating NFL story lines this season. And it was reinforced last Sunday, when Tebow led his underdog Denver Broncos to a surprise overtime victory against the Pittsburgh Steelers in the AFC Wildcard playoff game. The game turned out to be CBS’s most highly rated NFL Wildcard game in 25 years.

But the fervor surrounding Tebow has little to do with his actual playing ability. He’s an evangelical Christian who proudly and publicly backs conservative causes. That, of course, is not an anomaly in professional sports, nor should it be all that controversial. Yet it’s a prominent part of the narrative being written about Tebow as sports’ supposedly most endangered species: the underrated “good guy.” Or, through another lens: the white, God-fearing athlete who believes in so-called “traditional” family values.

Through that latter lens, Tebow’s narrative represents an enduring double standard in sports, one in which athletes are free to endorse conservative causes, while others are hounded as bad apples for progressive political stances, particularly those involving race. “Tim Tebow is just a window into how certain politics are not only respected, but they’re valued,” says David Leonard, a professor at Washington State University.

There’s no denying that Tim Tebow is a world class athlete. Before entering the NFL, he won a Heisman trophy and two national championships at the University of Florida on his way to becoming arguably the most celebrated player ever to take a college football field.

The Broncos drafted him in the first round of the 2010 NFL Draft. While his second season has seen some serious lows–including a humiliating loss to the Buffalo Bills in which he threw three interceptions, two of which were returned for touchdowns–they’ve by and large been the understandable pitfalls of a young quarterback who’s learning his way in the league.

But it’s Tebow’s devout Christianity that’s drawn the most attention. He was born in the Philippines to Baptist missionaries. In college, he made headlines when he wrote his favorite Bible verse, John 3:16 (about God’s salvation), under his eye in black. His tradition of bowing down on one knee and praying after each touchdown, now known as “Tebowing,” has been adopted by school kids and was even taken up this season by the U.S. Marines, when they made an appearance on the field before a Broncos game against the New York Jets.

More prominently, Tebow and his mother, Pam, were featured in a 2010 Super Bowl ad for Focus on the Family, an evangelical Christian anti-abortion group that’s based in Colorado. In the 30-second spot that aired on CBS, Pam Tebow recounts Tim’s traumatic birth, in which doctors recommended that she abort her fetus because of potentially deadly complications. “I call him my miracle baby,” Tebow’s mother says in the ad. “There were so many times when I almost lost him.”

“The impact of the ad campaign was $37 million worth of media attention,” Focus on the Family spokesperson Gary Schneeberger told USA Today. But Tebow did it for free.

The group provides grants and medical training to so-called “crisis pregnancy centers” where women must have ultrasounds before receiving an abortion–a fast-growing and widely criticized practice that reproductive rights advocates consider cruel.

In addition to its anti-abortion stances, Focus on the Family opposes LGBT rights and same-sex marriage. In 2005, the Southern Poverty Law Center called the group one of a “dozen major groups [which] help drive the religious right’s anti-gay crusade.” The group also threw its support behind the Federal Marriage Amendment, a law that would have defined marriage as a union between one man and one woman.

CBS was widely criticized by reproductive health providers like Planned Parenthood, especially because it had declined to run ads by left-leaning groups like the United Church of Christ,, and PETA.

While Tebow has been celebrated for his devotion to his ideals, athletes who take up progressive causes are often widely criticized–particularly when they’re black.

When news hit that U.S. special forces had killed Osama Bin Laden, Pittsburgh Steelers running back Rashard Mendenhall, who’s black, spoke out. “What kind of person celebrates death? It’s amazing how people can HATE a man they have never even heard speak. We’ve only heard one side…” he tweeted. Later, he added: “We’ll never know what really happened. I just have a hard time believing a plane could take a skyscraper down demolition style.” The tweets caused such an uproar that team president Art Rooney had to issue a statement to the press reinforcing the organization’s pride in the military.

Tebow’s defenders argue that it’s unfair to criticize him for his religious beliefs, and that they shouldn’t be mixed up with discussions about politics. But his critics contend that there’s no getting around the fact that he’s explicitly endorsing a conservative political agenda.

“It’s not about bigotry against an abstract Christianity,” says Dave Zirin of the criticism facing Tebow. Zirin is a sports columnist at The Nation and the author of several books. “It’s actually about political opposition to Focus on the Family and to a whole set of ideas that the media’s giving him a pass for.”

There’s a double standard for black athletes throughout the history of sports, Zirin says. “African American athletes who take political stands are vilified and even lose their livelihood.”

Perhaps the most widely known example of this was the 1968 Olympic games in Mexico City, where John Carlos and Tommie Smith each gave black power salutes after their performance in the 200 meter race. Both men were immediately suspended from the U.S. team and banned from the Olympic village, where athletes usually stay while competing in the games.

In 1996, NBA basketball player Craig Hodges sued the league, claiming that it blackballed him for his political activism. After Hodges helped the Chicago Bulls win the 1992 NBA Championship, he showed up to the team’s visit to the White House in a dashiki and delivered a hand written letter to then-president George H.W. Bush expressing his critical views of the administration’s policies toward poor and African Americans. That same year, he criticized mega star Michael Jordan for not being more politically active. The team waived him after the ‘92 season and he didn’t receive a single offer try out for another team.

Cases like Hodges’ are unfortunate, but they’re all too often the reality in pro sports, according to Leonard.

“When people say that politics have no place in sports, what they’re saying is that progressive politics, oppositional politics, counter narratives have no place in sports.”