Arizona Republican has strictly honorary roles with the McCain Institute for International Leadership, a program at Arizona State University, and its fundraising arm, the McCain Institute Foundation, according to his office. But McCain has appeared at fundraising events for the institute and his Senate campaign's fundraiser is listed in its tax returns as the contact person for the foundation.

Though federal law strictly bans foreign contributions to electoral campaigns, the restriction doesn't apply to nonprofits engaged in policy, even those connected to a sitting lawmaker.

Groups critical of the current ethics laws say that McCain's nonprofit effectively gives Saudi Arabia -- or any other well-heeled interests -- a means of making large donations to politicians it hopes to influence.

"Foreign governments are prohibited from financing candidate campaigns and political parties," Craig Holman, the government affairs lobbyist for ethics watchdog Public Citizen, said. "Funding the lawmakers' nonprofit organizations is the next best thing."