T-shirts are a powerful form of American expression. The ’60s, ‘70s and ‘80s were chock full of chic, racially specific slogans and images on T-shirts that amounted to an ongoing protest rally. Who can forget “Black Man’s Time”? Or the equally iconic: “Happy to be Nappy”?

But in the 1990s, that sort of in-your-face, activist statement became less visible, overtaken by shirts sporting images of snarling hip-hop artists. And now the dominant contemporary image on tees is the face that of President Obama.

But Renee Cox wants to make them racial and radical again. Cox is the founder of Maroon Rebel, a new Web site that hawks shirts and history, and she is challenging the notion that we have entered a post-race moment.

“I found it disturbing that the media was making references to watermelons on the White House lawn and comparing Obama to a gorilla,” Cox said. “However, due to the fact that we are in a ‘post race’ age, I choose to view their actions as ignorance instead of racism.”

Cox was at the center of a cultural firestorm more than a decade ago for her re-rendering of Da Vinci’s The Last Supper, “Yo Mamma’s Last Supper,” which featured her as a naked Jesus.

Cox, who was born in Jamaica and now resides in upstate New York, insists that the messages on his shirts are about reclaiming history and is convinced that African history and African-American signifiers are being repressed and forgotten, even by many black people.

“All the shirts have historical prompts, and that’s the point. I prefer to open up a dialogue about race using Maroon Rebel T-shirts,” Cox said. My hope is that people will actually look up what the slogan means.”

One shirt says “Hey Baby,” and in the small print below adds: “Emmett Till Died For This.” Another one, full of echoes, says: “Coloreds Only” with the tag line, “That Means Everyone,” in smaller type. Cox says it’s because some people don’t get the historical reference. “The word is no longer seen since Jim Crow, and people can’t even pronounce it anymore because it’s no longer PC. It’s been taken out of circulation. I don’t understand who said we should forget about it and just move on.”

As a message medium, T-shirts have worked and have been widely successful. Listen to my T-shirt, it’s telling you what I’m thinking.

Nick Charles is a regular contributor to The Root.