Martin McGuinness, a former commander of the IRA and Northern Ireland's deputy first minister, was officially confirmed on Sunday as his Sinn Fein party's candidate for next month's Irish presidential election.
The socialist republican party's executive, the Ard Chomhairle, unanimously backed a proposal to support the 61-year-old, with Sinn Fein president Gerry Adams saying: "He embodies everything that is needed in a political leader."
McGuinness must gather the support of 20 Irish lawmakers before nominations close on September 28, but Sinn Fein expressed confidence that he could do this.
He will struggle to win -- Sinn Fein won just 9.9 percent of the vote in February's general elections in Ireland, and the bookmakers have ranked him third behind candidates from the ruling Fine Gael and Labour parties.
But the decision to field a Sinn Fein candidate for the presidency for the first time ever is a sign of the party's growing presence south of the border.
McGuinness is an effective campaigner but he remains hugely controversial because of his militant past, despite his four years as the second most senior figure in Northern Ireland's devolved administration in Belfast.
He was a leading member of the Irish Republican Army (IRA), the paramilitary group responsible for much of the violence during the three decades of sectarian violence that plagued British-ruled Northern Ireland.
However, he was also a key player in the peace process. He was viewed as instrumental in the IRA's decision to hold a ceasefire and then give up its weapons, and was a chief negotiator for the landmark 1998 Good Friday peace deal.
Announcing his confirmation as Sinn Fein's candidate in Dublin on Sunday, Adams said: "Martin would truly be a president for all Ireland and all Irish people, wherever they are."
"He has a deep love of Ireland and her people, and more importantly a vision of where Ireland as a nation needs to go."
The election, which will decide the successor to president Mary McAleese, who has held the purely ceremonial post for two terms, takes place on October 27.
McGuinness will not necessarily have to resign his position in Belfast during the campaign. Commentators suggest he could take a leave of absence, and appoint a caretaker minister in his place.