John McCain's presidential campaign team is asking staff to disclose all previous lobbying ties following the resignation of two officials linked to a firm that worked for Burma's military junta.
A memo from Mr McCain's campaign manager, Rick Davis, also instructs staff to make certain they are no longer registered as lobbyists or foreign agents.
It was issued following the resignations of Doug Goodyear, who was to run the Republican National Convention, and Doug Davenport, a regional campaign director for the mid-Atlantic states. Both worked for DCI Group, a consulting firm hired to improve the image of Burma's junta.
"I found out that two people had, some years ago, been involved with the government of Burma, so I needed to fix the problem, and we needed to fix it policy-wise," Mr McCain told reporters on his campaign bus.
Past lobbying work does not automatically disqualify someone from working for the campaign. Mr Davis and another senior adviser to McCain, Charlie Black, were long-time lobbyists but have now severed their lobbying ties.
Like Goodyear and Davenport, Mr Black and Mr Davis have lobbied for foreign governments. The campaign also has other staffers and advisers who are registered lobbyists.
Campaign spokeswoman Jill Hazelbaker refused to comment on any individual aides but said they must sever their ties or leave the campaign. Advisers or other part-time volunteers must disclose their ties and, if they have lobbied, stay away from campaign policymaking, under the new policy.
On Thursday, when the policy was announced, Mr McCain sacked an energy policy adviser Eric Burgeson, who represents energy companies as a lobbyist.
The campaign also asked Craig Shirley to step down as a member of Mr McCain's Virginia leadership team because he was behind an independent group that had been criticising Democratic rivals Hillary Clinton and Barack Obama on the internet.
That is because Mr McCain's new policy 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.
Aides would not say yesterday if the memo prompted any other departures from the campaign.
Democrats have spent months pointing out the lobbying ties of Mr Davis, Mr Black and other McCain advisers. They argue that Mr McCain's relationships with lobbyists belie his reputation as a reformer of money in politics.
"Senator McCain asking his lobbyist pal Rick Davis to 'clean the lobbyists' out of his campaign is like a farmer asking a fox to guard the hen house," Democratic National Committee spokesman Damien LaVera said.
Democrats have ties to lobbyists too however, and the debate is likely to persist.
Mrs Clinton's top aide, Mark Penn, was demoted after word surfaced that he had met Colombian government representatives to help promote a trade agreement that Mrs Clinton opposed. Mr Penn worked as the chief executive of the public relations firm Burson-Marsteller.
Mr Obama does not take contributions from lobbyists, but does have advisers who are lobbyists. He has not released a complete list of the lobbyists who advise him.