The state of South Carolina faces a federal lawsuit seeking to block its plans to issue license plates which feature a bright-yellow Christian cross on a multicolored stained glass window and the words “I Believe.”

The bill permitting the license plates passed the state legislature unanimously, while South Carolina governor Mark Sanford allowed the bill to become law without his signature, CNN reports.

A similar design had been considered in Florida but was rejected because of First Amendment concerns.

"I think it allows people of faith to profess that they believe in a higher calling, they believe in God," said South Carolina Lt. Governor Andre Bauer, who has offered to personally pay a $4,000 deposit required for the state’s Department of Motor Vehicles to begin production of the plates.

The Rev. Barry Lynn, executive director of Americans United for Separation of Church and State, is leading the opposition to the law. He claims Bauer’s involvement “more deeply confirms this is a government-sponsored program.”

"I don't believe that these license plates will ever be on any car in South Carolina, because I think our constitutional claim is so strong," Lynn said, according to CNN.

Individuals can ask the DMV to print plates for other faiths, for a $4,000 fee, but the request is allegedly subject to significant limits and rules not imposed for the Christian plate. Other tags could feature a religious symbol, but no words would be allowed.

"The state has made believers of non-Christian faiths feel that they are second-class citizens," Lynn continued. "Under our Constitution, that's impermissible."

Andre Bauer responded by arguing that the provision of Christian plates was an issue of freedom of speech.

“We're not going to back down," Bauer said, according to CNN. "We're going to fight for a change. I'm tired of seeing Christians back down in fear of a lawsuit."