The IRA took a long time to go away and the same can now be said of the searching questions facing Martin McGuinness. He is finding that the Irish presidential election is a different ball-game to the peace process in Northern Ireland.

So desperate have people here been to preserve peace that air-brushing the past has become a political pastime. Not so in the Republic.

The media will not let go, nor will the established parties down south, which can now see Sinn Fein using the election as a platform to gain more support.

Martin McGuinness can expect to be put on more embarrassing spots. He is getting the message belatedly that he will not be taken at his smiling face-value.

This is in contrast to the experience of republican and loyalist leaders in Northern Ireland, where the price of peace has been to ignore, excuse, and even forget about the brutality of a past which destroyed so many lives.

I felt that last week about McGuinness and also the loyalist leader Gusty Spence, who went to his grave revered in some quarters as a man of peace when he was nothing of the sort for much of his life.

I am old enough to recall Spence's early involvement in the murder of a young Catholic barman, Peter Ward, on the Shankill Road in 1966.

As a trainee reporter at the time, I was sent to Belfast court to shadow an experienced journalist who was covering Spence's trial. I had never seen a murderer before and sat, somewhat transfixed, looking across at Spence and his two accomplices. To this day, I can still see their steely faces in the dock.

With the passage of time, it is too easy to forget what dreadful pain and terror Spence - and Martin McGuinness - imposed on our society for so many years before they belatedly saw the light.

The questions now being raised in the Irish presidential election are a reminder that the vast majority of people in Northern Ireland - law-abiding Protestants and Catholics, unionists and nationalists alike - were powerless to stop loyalist and republican terrorism supported by Spence and McGuinness.

Both men are given credit for the peace process, but both ignored the people's call for an end to violence for far too long.

Martin McGuinness, in standing for the presidency of Ireland, has turned a spotlight on his life. He now appears to be distancing himself as never before from the excesses of the IRA, such as the Enniskillen bombing.

Twenty-five years is a long time to wait for a potential Irish president to say he is "ashamed". So he should be, but whether his past will haunt him at the ballot box remains to be seen - especially among young voters who have no memory of his IRA connections.

The crying shame for Ireland is that Martin McGuinness, in all his orations at republican gravesides and speeches to Sinn Fein conferences over the years, never expressed remorse as he is doing so now.

From the critical southern reaction to him, it is just possible that his candidacy will prove a rare mistake in Sinn Fein's strategy.

Perhaps the party would have been better to have selected a candidate with less of a direct link to the IRA and one who could speak more freely about his, or her, past.

He has answered one question in relation to Enniskillen - an atrocity which shocked the world. But there are so many others.

Even the parish priest, Father Michael Canny, who attended the McGuinness campaign rally in the Bogside, says: "I have no problems about people questioning Martin about anything on this campaign and any part of his life should be held up to scrutiny and I think that Martin is the only person who can answer those questions."

For all his constructive work in Northern Ireland, Martin McGuinness has become the butt of ridicule in some quarters of Dublin.

So much of his life and times remains a closed and secretive book. The election campaign, to date, is merely reminding him - and us - of this painful fact.

More so than any of the other candidates, he cannot be open and transparent.

Sinn Fein is entitled to have an official nominee for president, but the party risks insulting the integrity of the office by its selection of someone with so much to hide.