A national co-chairman of Senator McCain’s presidential bid, Thomas Loeffler, has quit less than a week after a report in The New York Sun highlighted his work as a registered lobbyist for Saudi Arabia.

“Mr. Loeffler has resigned his position with the campaign,” a spokesman for Mr. McCain, Tucker Bounds, said yesterday. He would not elaborate on the reasons, but the departure comes on the heels of the campaign’s issuance of a new conflict-of-interest policy that prohibits campaign staffers from simultaneously working as lobbyists.

Earlier this month, the CEO of the Republican National Convention in Minneapolis, Douglas Goodyear, and a regional campaign manager for Mr. McCain, Douglas Davenport, resigned over work they did in 2002 for the military junta that rules Myanmar, more commonly known as Burma.

However, the Sun reported that other campaign aides with more recent ties to regimes accused of serious human rights violations were still working for Mr. McCain. Among them was Mr. Loeffler, whose lobbying firm, Loeffler Group, has collected nearly $15 million from Saudi Arabia since 2002.

Newsweek and other news outlets described Mr. Loeffler, who was a congressman of Texas between 1979 and 1987, as a co-chairman of Mr. McCain’s national finance committee. However, that description understates the role played by the Washington power broker. In March 2007, Mr. McCain’s campaign announced that Mr. Loeffler was being elevated to the post of general co-chairman and would “be closely involved in the daily workings of the campaign, and assist with fundraising, strategy, and message development.”

Last week, an aide to Mr. McCain acknowledged that Mr. Loeffler was working full-time on the campaign, though he did not draw a salary.

Mr. Loeffler did not respond to an e-mail message seeking comment for this article, but last month he denied lobbying the senator of Arizona. “At no time have I discussed my clients with John McCain, and there have been many occasions where he has voted against my clients’ interests,” Mr. Loeffler told the Washington Times.

In fact, lobbying disclosures filed by Mr. Loeffler’s firm show he escorted the Saudi ambassador to America, Prince Turki, to a meeting with Mr. McCain in May 2006 to discuss “U.S.-Kingdom of Saudi Arabia relations.” The meeting was first noted earlier this year by ABC News and the Center for Investigative Reporting.

The bigger problem for Mr. Loeffler may not have been the work he did for the Saudis, but the work he didn’t do. Between June and November 2007, his firm was paid nearly $1 million by the Saudis, but reported no meetings with lawmakers, American officials, or anyone else. “It seems like an awful lot of money to be paid for twiddling your thumbs,” William Alston of the Sunlight Foundation, which first noted the discrepancy last month, said. “It almost looked like an investment in a potential McCain presidency.”

Newsweek reported that a former staffer at Loeffler Group, Susan Nelson, is dropping a $15,000 a month consulting contract there in order to keep working full-time as Mr. McCain’s finance director. Another Loeffler Group lobbyist on the Saudi account, Hans Rickhoff , was listed on the Washington Steering Committee of Young Professionals for McCain. It is unclear what role if any he played on the campaign.

“This policy has just been initiated and we’re working through the policy,” Mr. Bounds said.