Obama, D-Ill., won't accept federally registered lobbyists' money but does have a high-powered individual lobbyist helping to raise money for the Democratic National Convention in Denver, the Politico said.

And while McCain, R-Ariz., doesn't want lobbyists' representatives on his staff, some old-fashioned horse-trading, notably by Republican Gov. Tim Pawlenty, rumored to be on McCain's short list of running mates, is going on to get corporations to pony up funds for the Republican shindig in St. Paul, Minn.

Besides the candidates' seemingly contradictory stance about lobbyists on their payroll, there's a large loophole in campaign finance laws that allow convention host committees to accept otherwise unacceptable donations because they're not driven by civic pride, not politics, the Washington publication said.

Stephen Weissman of The Campaign Finance Institute told Politico that corporate donations to host committees skyrocketed after the campaign financing changes were implemented.

Since 2005, U.S. corporations have donated nearly $100 million to candidates and parties through political action committees and personal checks.

"Now, they are drawing directly upon their corporate treasuries" to finance the conventions, Weissman said, "which will extend their lobbying reach."