The list, which has come under fire from conservatives for being too left-leaning, is based on a combination campaign finance violations, flagrant rules violations, credible allegations of corruption and other factors.

The nonpartisan Center identifies the 14 most corrupt members, and also points out a few "Dishonorable Mentions."

While some of the people on this year's list have been serial offenders of Ethics rules on the Hill, some are new — and some are unexpected.