Funny, I just looked into this last night! Apparently he's actually a 'grafter'
The grifter is a small-time confidence man, a carnival swindler, or thief of some sort or other. The grafter may be most of these things, but also may be someone who engages in the “political corruption” sense of the word graft (which we define as “the acquisition of money, position, or other profit by dishonest or questionable means, as by actual theft or by taking advantage of a public office or a position of trust or employment to obtain fees, perquisites, profits on contracts, or pay for work not done or service not performed”).