WordNet (r) 3.0 (2006):

influence peddler
    n 1: someone who intervenes with authorities for a person in
         trouble (usually using underhand or illegal methods for a
         fee) [syn: fixer, influence peddler]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "influence peddler":
   Machiavel, Machiavellian, Machiavellianist, Rasputin, Svengali,
   VIP, access, bad influence, big wheel, boodler, court,
   crooked politician, diplomat, diplomatist, eminence grise,
   five-percenter, fixer, four-percenter, friend at court,
   good influence, grafter, gray eminence, heavyweight, hidden hand,
   influence, influencer, ingroup, jackleg politician, key, kingmaker,
   lobby, lobbyist, logroller, lords of creation, man of influence,
   manipulator, open sesame, political realist, politician,
   power broker, powers that be, pressure group, sinister influence,
   special interests, special-interest group, spoilsman, spoilsmonger,
   the Establishment, very important person, wheeler-dealer,
   wire-puller