W. Samuel Patten is an American political consultant and lobbyist who received international attention in 2018 in relation to the Special Counsel investigation led by former FBI director Robert Mueller. In spring 2018, this was due to Patten's relationship with Konstantin Kilimnik, a subject of the investigation. In summer 2018, attention intensified due to Patten's emergence as a subject of the investigation in his own right, followed by his guilty plea, after being charged in August 2018 with violating the Foreign Agents Registration Act for failing to register as a foreign agent with the Justice Department when he represented the Opposition Bloc, a Ukrainian political party, from 2014 through 2018.