WASHINGTON - John McCain's national finance co-chairman has stepped down, the latest casualty of a presidential campaign eager to cauterize damage caused by its ties to lobbyists.

Former Texas Rep. Thomas G. Loeffler, one of McCain's key fundraisers, resigned in the wake of a new McCain policy on conflicts of interest that required campaign volunteers to disclose their lobbying connections.

"Mr. Loeffler has resigned from his position with the campaign," McCain spokesman Tucker Bounds said yesterday.

Loeffler, who runs the lobbying shop The Loeffler Group, is the highest profile departure from McCain's inner circle since a summer 2007 shake-up cost McCain his campaign manager and chief strategist.

Among Loeffler's clients is the European Aeronautic Defence and Space Co., the parent company of plane manufacturer Airbus. Northrop Grumman Corp. and EADS won a lucrative contract to provide air refueling tankers for the Air Force. McCain helped scuttle an earlier contract in 2004 that would have gone to an American competitor, Boeing Co.

Loeffler's firm also has lobbied for other foreign interests and foreign governments. Newsweek reported over the weekend that Loeffler's firm was paid $15 million by Saudi Arabia. The news magazine also said Loeffler listed meeting McCain along with the Saudi ambassador to "discuss U.S.-Kingdom of Saudi Arabia relations," even though Loeffler told a reporter last month that he had not discussed his clients with McCain.

McCain's new policy prohibits any staffer on the campaign from being a registered lobbyist or foreign agent. Part-time volunteers for the campaigns, such as Loeffler, have to disclose whether they are registered lobbyists or lobbying on behalf of foreign entities.

Under the policy, dated May 15, such volunteer advisers cannot lobby McCain or his legislative staffs during the period they serve on the campaign.

The work of lobbyists close to McCain had become fodder for critics, undermining McCain's image as a reformer who has tried to restrict the influence special interests in government.

McCain advisers Doug Goodyear, who was to run the Republican convention in St. Paul, Minn., and Doug Davenport, a regional campaign director for the Mid-Atlantic states, also resigned this month. Both worked for DCI Group, a consulting firm hired to improve the image of Myanmar's military junta.

When the policy was announced last week, McCain fired energy policy adviser Eric Burgeson, who represents energy companies as a lobbyist.

The campaign also asked Craig Shirley to resign from McCain's Virginia leadership team because he was behind an independent group that has been criticizing Democrats Hillary Rodham Clinton and Obama on the Internet. McCain's new policy also states that no one with a campaign title or position may participate in so-called 527 groups, which can raise unlimited amounts of money for television ads not controlled by campaigns.

But the policy also underscored the fine line McCain has drawn. Several top strategists working on his campaign are lobbyists who have taken leaves of absence from their jobs to work for McCain. Among them are campaign manager Rick Davis, whose past clients have included a Russian industrialist, and Charlie Black, a high profile Washington lobbyist with domestic and foreign clients. *