As part of its effort to court supporters on Capitol Hill several years ago, mortgage giant Freddie Mac hired Mark Buse as a lobbyist. Buse was a longtime confidant of Sen. John McCain, and at the time, Freddie Mac feared that the senator was too outspoken on executive pay, an issue of intense concern for the highly-compensated chiefs at Freddie, The Post's Matthew Mosk and David S. Hilzenrath report.

Buse is now chief of staff at McCain's Senate office. In 2003, Buse reportedly was given credit inside Freddie when McCain, as chairman of the commerce committee, declined to pursue legislation addressing Freddie Mac and Fannie Mae, another mortgage giant, saying that the panel lacked jurisdiction. McCain aides say that the hiring of Buse had no influence on the senator's decision-making. They point out that McCain co-sponsored a bill to overhaul regulation of Fannie and Freddie in September 2003 and again in 2006.

Over the past decade, Freddie Mac spent more than $95 million on lobbying, and its efforts were emblematic of the interconnections among Fannie, Freddie and the lawmakers whose support was critical for their business.

Buse led the Republican commerce committee staff in the late 1990s and early 2000s (and, at one time, was the chief liasion between McCain and the Bush administration), and was a lobbyist for ML Strategies, representing eBay, Goldman Sachs Group, Cablevision, Tenneco and Novartis Pharmaceuticals.

Buse's lobbying connections have come under scrutiny before.

Arizona rancher Fred Ruskin told The Post in May that he had hired Buse in 2002 to help him negotiate a complicated land swap with the federal government.

"I had gone to him to see if he had any advice as to how to deal with McCain," Ruskin said. "We had a couple of meetings and I paid him a little bit."

Buse's federal lobbying records do not list the ranch as a client.