Republican presidential candidate Herman Cain in an interview Sunday refused to name the economic advisers that helped develop his 9-9-9 plan, saying that he didn't want to "compromise their confidentiality" by attaching their names to his campaign.

"They have their own independent businesses and I don't want to compromise their confidentiality at this point," Cain said. "When they tell me it's OK to mention their names publicly, I will mention it. But trust me, it was a couple of people you know very well."


Chris Wallace of "Fox News Sunday" pressed the candidate, noting that rivals such as former Massachusetts Gov. Mitt Romney had their economic plans openly vetted by Ivy League economists.

“The chairman of my economic advisers is a gentleman by the name of Rich Lowery of Cleveland, Ohio. He worked with a couple of other people — quite frankly, that are well known — that I’m not at liberty to mention their names,” Mr. Cain said.

Cain's plan would replace the current tax code with a 9 percent flat tax on business and personal income and an additional 9 percent national sales tax. Critics have argued that the plan would shift tax burdens to low- and middle-income American families.

Cain's refusal to name staff came a week after a former staffer testified that the campaign tried to hide the work of the openly gay treasurer of his political action committee (PAC) because his sexual orientation made supporters uncomfortable.

Former staffer Kevin Hall, who helped Cain coordinate for the Iowa straw poll, said the Cain campaign told staffers to tell donors and supporters that Scott Toomey, a former Cain adviser, was no longer involved in the campaign. But Toomey continued to work closely with the campaign as an outside consultant, allowing Cain staff to say that Toomey had left the campaign — and removing any mention of Toomey in Federal Election Commission filings — while, for all intents and purposes, he maintained the same role.

"A conservative candidate, Mr. Cain is on the record as stating that he believes homosexuality is a sin and a choice. And they know that, if his top adviser, his highly paid adviser, is openly gay, that it would cast a negative light on Mr. Cain and would cost him in his efforts to become president," Hall testified. "Basically the campaign was trying to cover up the fact that Mr. Toomey was still involved. They asked … me to help them cover up that fact."

Cain campaign spokeswoman Ellen Carmichael told The Associated Press that Hall was "a disgruntled former staffer" and that his claims should be viewed skeptically through that prism. She also said that Toomey is no longer a Cain staffer or consultant, but that his sexuality was not the reason for his departure.