Rick Davis, the manager of Senator John McCain’s presidential campaign, is a typical Washington insider in many ways, having long worked as both a lobbyist and a political operative along the intersection of politics, policy and money.

Now Mr. Davis is overseeing new lobbyist-related guidelines that the campaign has issued in an effort to safeguard Mr. McCain’s reputation as an opponent of special interests. The plan, among other things, bars “registered” lobbyists, those who must file disclosure reports listing their clients, from working on the campaign.

Mr. Davis, who last worked as a registered lobbyist in 2005 and took a leave from his lobbying firm in 2006, appears to meet those guidelines. Still, his own business dealings in recent years  roles that include consultant and investor  extend beyond lobbying and illustrate the limits of the guidelines in defining what it means to be selling expertise and helping to provide access.

Take Mr. Davis’s involvement with one of his lesser-known lobbying clients, an Israeli company, Imagesat, which sells satellite imagery. Along with lobbying for it, Mr. Davis became a consultant to a private investment firm that had a financial stake in it. That connection opened the door for him to get in on the ground floor of other investments made by the firm, Pegasus Capital Advisors.