Martin McGuinness (James Martin Pacelli McGuinness), 1950–, Northern Irish political leader. He joined the Irish Republican Army (IRA) as a young man and was active in both its regular and provisional wings. He was convicted of membership in the IRA by the Republic of Ireland in 1973 and served a prison term; he claimed to have left the IRA in 1974. A member of Sinn Féin, McGuinness was elected to the British parliament in 1997 (and 2001, 2005, and 2010), but like other members of the party refused to take his seat; he resigned his seat in 2012. A member of the Northern Irish Assembly since 1998, he has served as minister of education (1999–2002) and deputy first minister (2007–). McGuinness ran unsuccessfully in the Republic of Ireland's presidential election in 2011.