A judge who sent an email to friends that contained a racist joke involving bestiality and President Barack Obama's mother has asked a court to conduct a judicial misconduct review.
Montana judge Richard Cebull (pictured) plans to send Mr Obama a formal apology, but that has not halted calls for his resignation.
"If he has any respect for his office and for ideals of equality and human dignity on which our country was founded, Judge Cebull will step down," said Bob Edgar, president and chief executive of Common Cause, a good governance advocate.
Common Cause filed a complaint yesterday against Judge Cebull with the US 9th Circuit Court of Appeals.
Judge Cebull also asked for a review by the court, effectively filing a complaint against himself.
The appellate court's judicial council will lead the investigation and "is expected to act expeditiously", court executive Cathy Catterson said.
Judge Cebull admitted on Wednesday that he forwarded the email on February 20, but said he did so because he disliked Mr Obama, not from racism.
"I didn't send it as racist, although that's what it is. I sent it out because it's anti-Obama,"Judge Cebull told the 'Great Falls' newspaper.