Washington ? The tea party leader who penned an incendiary and racially derogatory blog post has resigned his position with a prominent conservative group, refusing to apologize but saying he no longer wished to be used as “ammunition” in the “war for the future of this country.”

The resignation of commentator Mark Williams as a spokesman of the organization known as the Tea Party Express, announced Friday, marked the latest in a series of fractures within the conservative movement as it confronts charges that it tolerates racism and fringe political elements.

“I am going to continue to fight on the side of liberty but it is clear that doing so with any affiliation with the Tea Party Express is not the best way to do so,” Williams wrote, according to a letter circulated by the Sacramento, Calif.-based political action committee.

Williams adding that he did not want “the media and our domestic enemies” to portray him as the chief spokesman for the larger conservative movement.

A portion of the larger tea party movement shunned Williams and his Tea Party Express earlier this week, citing a blog post in which Williams wrote a mock letter to Abraham Lincoln from NAACP President Benjamin Jealous.

“Freedom means having to work for real, think for ourselves, and take consequences along with the rewards. That is just far too much to ask of us Colored People and we demand that it stop!” the letter read.

Williams’ letter was a response to a decision by the civil rights organization to adopt a resolution earlier this month that branded elements of the tea party movement as racist.

Williams described his response as satire, but the National Tea Party Federation, representing the larger movement, called it an “embarrassment.”