Leading article: Another big step forward

Martin McGuinness and the IRA have a lot to answer for. This organisation was responsible for almost half the deaths of the Troubles; it sent around 1,800 people to early graves. The republican movement took a couple of decades to transform itself from a ruthless killing machine into a purely political entity, but Mr McGuinness, Gerry Adams and the rest of the leadership have managed this with striking success.

In the north, Sinn Fein is the second largest party, while in the south it is joint third. Republicans reached this point, first by persuading other Irish nationalists that peace was possible, then by bringing Tony Blair and Bill Clinton aboard. Finally, and most astonishingly, they persuaded the Reverend Ian Paisley that they were in earnest. The IRA put its guns beyond use and left the stage. Sinn Fein was accepted into government in Belfast, Mr McGuinness and Mr Paisley working together so well they became known as the Chuckle Brothers.

With the IRA guns gone, Sinn Fein deployed a new secret weapon: Martin McGuinness – who made the switch from IRA offensive to charm offensive. In the Belfast Assembly he has been adept at winning friends and influencing people. And while Mr Paisley has left the scene, Mr McGuinness has formed a close relationship with his successor, Peter Robinson. This year's Assembly election result, which put the two parties well ahead of all others, was a resounding endorsement of the McGuinness-Robinson double-act which today runs Northern Ireland.

The IRA left many with physical and emotional scars, and the enduring hurt has been expressed by Lord Tebbit and others. It is 27 years since he and his wife were injured by the IRA Brighton bomb, and the pain is still palpable. But in Ireland, north and south, Mr McGuinness has been key to establishing newly minted democratic credentials for his movement, and conveying the message that today's republicanism is about politics alone.

It is his new status that has emboldened Sinn Fein to put him forward in the south. The sight of him standing for President stirs painful emotions for many. Yet at a deeper level it is another positive step in republicanism's long journey away from its violent history, away from the gun and into politics.