Douglas Holtz-Eakin
The former Congressional Budget Office head, known as a fiscal hawk, is McCain's top economic dog. The two bonded over McCain's fight against a Boeing plan to lease aircraft tankers to the Air Force.
Jack Kemp
The former N.F.L. quarterback, congressman, Housing and Urban Development secretary (under George H.W. Bush), and champion supply-sider lines up with McCain on tax cuts.
Steve Forbes
The publisher and erstwhile presidential candidate switched to McCain after Giuliani flopped. Forbes' big push: a flat-tax system in which everyone pays the same rate.
Peter Peterson
The Blackstone Group co-founder and economic Cassandra has McCain's ear. Peterson has long been an advocate of means-testing entitlement programs. He says he's too rich to get Social Security.
Carly Fiorina
The former Hewlett-Packard chairwoman is a leader of G.O.P. fundraising efforts for the general election. She is advising McCain on tech and investment issues.
John Thain
The Merrill Lynch boss and former New York Stock Exchange C.E.O. was an early McCain man. If McCain wins, Thain could be a leading candidate for the post of Treasury secretary.
Phil Gramm
McCain was one of only a handful of senators to support Gramm's bid for president in 1996. Gramm, who fathered various federal-budget-cutting mandates, is repaying the favor.