In 1985 , O'Brien supported unionist objections to the inter governmental Anglo-Irish Agreement . In 1996 he joined Robert McCartney 's United Kingdom Unionist Party ( UKUP ) and was elected to the Northern Ireland Forum . In 1997 , a successful libel action was brought against him by relatives of Bloody Sunday victims for alleging in a '' Sunday Independent '' article in 1997 that the marchers were " Sinn Féin activists operating for the IRA " . O'Brien opposed the 1998 Good Friday Agreement and opposed allowing Sinn Féin into government in Northern Ireland . He later resigned from the UKUP after his book '' Memoir : My Life and Themes '' called on Unionists to consider the benefits of a united Ireland to thwart Sinn Féin . In 2005 he rejoined the Labour Party . O'Brien defended his harsh attitudes and actions towards Irish republicans , saying " We do right to condemn all violence but we have a special duty to condemn the violence which is committed in our name "
Bloody Sunday
Bloody Sunday (1972)
Conor Cruise O'Brien