Updated

The only congressional Democrat to earn an endorsement from a prominent Tea Party group has rejected that support over a controversial blog penned by its former chairman.

Freshman Rep. Walt Minnick, D-Idaho, on Monday wrote to the Tea Party Express informing the group that he would no longer accept its April endorsement after activist Mark Williams wrote a racially charged "letter" on his website that slammed the NAACP.

"The reprehensible blog post by your spokesman was clearly in poor taste. Whatever his reasons for writing it, his words reflect on all of those associated with the Tea Party movement," Minnick wrote in a letter to co-chairwoman Amy Kremer. "Since the Tea Party Express refuses to reject and rebuke Mr. Williams, I have no choice but to decline your endorsement."

The move marked the latest fallout for the Tea Party Express from Williams' comments. The National Tea Party Federation, an umbrella group, over the weekend expelled Williams and his conservative outfit from its ranks after the Tea Party Express declined to oust Williams.

The Tea Party Express could not be reached for comment about Minnick's decision.

It's unclear how the move will affect Minnick's chances at reelection. He is the first Idaho Democrat to hold a seat in Congress since 1995 and in April reluctantly accepted the Tea Party Express support. A spokesman told the Huffington Post at the time that while being in the same league as outspoken Republican Reps. Joe Wilson, S.C., and Michele Bachmann, Minn., "is not something we are embracing," the congressman would not turn down the support.

Minnick's complaint on Monday stemmed from a satirical letter to President Lincoln Williams posted on his website, written from the perspective of NAACP President Benjamin Todd Jealous. He wrote it after the NAACP accused Tea Party members of racist behavior in a resolution approved at its convention last week.

"We Coloreds have taken a vote and decided that we don't cotton to that whole emancipation thing," Williams wrote.

He continued: "Mr. Lincoln, you were the greatest racist ever. We had a great gig. Three squares, room and board, all our decisions made by the massa in the house. Please repeal the 13th and 14th Amendments and let us get back to where we belong."

Williams later removed the letter from his website, acknowledging that the wording "was indeed objectionable."

Minnick said in his letter that he appreciates Tea Partiers' "recognition" of his fiscal responsibility credentials and that he finds most Tea Party members to be "cordial, polite and sincere."

However, he said those who "say or do hateful, hurtful things" harm the group and that the "proper response ... was not to use inflammatory sarcasm."

Williams and Tea Party Express coordinator Joe Wierzbicki issued lengthy statements after the expulsion dismissing the move and ridiculing the federation -- an upstart group formed in April with the help of the Tea Party Express.

"The Tea Party Express with over 400,000 members is by far larger than the Tea Party Federation's entire membership," Wierzbicki said. "Most rank-and-file Tea Party activists think we're talking about Star Trek when we try to explain who the 'Federation' is. Given the absurdity of the actions by the 'Federation,' this is quite fitting, since their conduct is alien to our membership."