GOP leaders say McCain has largely Black, a key campaign adviser, to thank for securing the backing of leading conservatives back when McCain's presidential bid was teetering on the brink of implosion.

Black traces his roots as a campaign adviser to 1972. He emerged as one of Washington's most embedded lobbyists, working for everyone from the Phillip-Morris tobacco giant to Iraq's Ahmed Chalabi and the Iraqi National Congress, The New York Times reported Sunday.

Critics point to the apparent conflict of interest between McCain, who opposes the power of special interests, and Black, whose influence in the Reagan White House was so strong, officials gave his firm enough time to cancel a Philippine contract before Reagan withdrew his support for Philippine President Ferdinand Marcos.

Black advises McCain on the campaign trail, showing up at news conferences and other appearances, and describes McCain as the true candidate of change.

"I've always believed you're in politics to help these candidates and not yourself, and you should stay out of the news if you can," he said.