BOISE - The lone Democrat to win favor with the Tea Party Express rejected the endorsement Monday, calling a group spokesman's controversial blog posting about the NAACP "reprehensible."

In a letter to Tea Party Express Chairwoman Amy Kremer, U.S. Rep. Walt Minnick said he had no choice but to decline the endorsement after the group refused to publicly rebuke and oust spokesman Mark Williams.

The group "has apparently decided to stand by Mr. Williams and support him," said Minnick, a first-term Democrat who represents Idaho's 1st Congressional District. "I cannot agree with that course of action."

The National Tea Party Federation said Sunday the Tea Party Express had been expelled from its ranks for refusing to remove Williams.

The conservative talk radio host posted a blog satirizing the NAACP and referred to its president Benjamin Jealous as "Tom's nephew and NAACP head colored person."

In a blog posting Sunday, Williams said he was refusing media interviews because he did not want to further inflame the situation. He noted he had pulled his "inflammatory (and arguably over the top - just ask my wife) criticism of the NAACP."

The NAACP approved a resolution last week calling on tea party activists and others to "repudiate the racist element and activities" within the political movement.

Tea party organizers say racism does not have any place in their activities. Minnick, a fiscal conservative who voted against federal bailouts and called for a permanent ban on earmarks, landed on the Tea Party Express list of "Tea Party Heroes" in April.

During the Idaho primary to pick a Republican challenger, the state's biggest tea party organization endorsed state lawmaker Raul Labrador, who won the nomination.

In his letter, Minnick said his interactions with tea party activists in Idaho have been "very positive," and he has found members of the movement to be polite and sincere, with their passion focused on the issues.

"However, those who rise to or claim leadership in those movements have an obligation to lead with respect for the movement and its members, and thus be responsible with words and actions," Minnick said.