Ruairí Ó Brádaigh, born 1932 in County Longford, Ireland is the current President of Republican Sinn Féin. He previously was President of Provisional Sinn Féin, from 1970–83, having been a leading figure in the Provisionals at the time of the split inside Sinn Féin into the Provisional and Official wings.

He also was prominent inside the Irish Republican Army. Ó Brádaigh was convicted for activity related to the Derrylin Raid, in County Fermanagh in December 1956, and was sent to Mountjoy Prison . In Mountjoy, he was elected to the Dublin parliament at Leinster House or Dáil Éireann. Upon completing his prison sentence he was interned in the Curragh Internment Camp , along with other Republicans. With the late Dáithí Ó Conaill (David or Dave O'Connell), Ó Brádaigh escaped from the camp and went "on the run" — the first Irish TD (Teachta Dála, member of the Dáil) on the run since the 1920s. He served as the IRA's Chief of Staff and was instrumental ending the IRA's "Border Campaign" in 1962.

With Dáithí Ó Conaill he developed a policy called Éire Nua during the 1970s. The policy called for a federal Ireland, and the goal of a federal Ireland became Provisional Sinn Féin policy in 1972. Federalism was rejected at the 1982 Provisional Sinn Féin Árd Fheis (party convention) and Ó Brádaigh and Ó Conaill, Provisional Sinn Fein Vice-President, resigned their positions at the 1983 Árd Fheis.

In 1986 Provisional Sinn Féin, led by Gerry Adams, dropped its policy of abstaining from taking seats (if its candidates were elected) in the Dáil. At this, Ó Brádaigh, Ó Conaill, and several others who agreed with their opposition to the change, walked out of the Ard Fheis and went on to form Republican Sinn Féin. Republican Sinn Féin adopted, and enhanced, its Éire Nua policy.