Students have vowed to protest or block North Carolina State University's Free Expression Tunnel until the university's chancellor gives guarantees that no hate speech will be allowed there. About 40 students painted the tunnel black overnight to protest racist and homophobic graffiti involving President Barack Obama painted there Sunday night. Slurs and the name "Obama" were painted over the picture of a black man. "It's not about the N-word. It's not about Obama. It's about racism, period,"