It remains to be seen whether last night's Prime Time debate can change the trajectory of this general election campaign.
But the aftermath has been dominated by controversy over how Sinn Féin responded to the death of 21-year-old Paul Quinn who was brutally murdered in Monaghan 13 years ago.
A pause before Mary Lou McDonald’s response to Miriam O’Callaghan’s questions on the issue betrayed a discomfort on the Sinn Féin leader’s part. That has been her experience of dealing with it in these final days of the campaign.
Her pause came before she accepted she was wrong in telling Bryan Dobson just 24 hours earlier that a senior party colleague in the North, Conor Murphy, had never accused Paul Quinn of being a smuggler and a criminal.
It turns out that he had. And those comments by Mr Murphy have been a source of hurt and pain and insult for Mr Quinn’s mother Breege and her family.
This is the discrepancy in what Ms McDonald has said:
In the Monday night interview she told Bryan Dobson: "I have spoken to Conor Murphy about this issue before. He is very clear that he never said that. That that is not his view and certainly I will talk to Conor again to clarify this matter."
On Tuesday, Prime Time quoted verbatim what Mr Murphy had said on the BBC in November 2007: "Paul Quinn was involved in smuggling and criminality. I think everyone accepts that. As I say, this is a very difficult situation as there is a family grieving and I don’t want to add to their grief."
Ms McDonald accepted this and said: "Those things should not have been said, Conor withdraws and apologises for them."
This morning, after a moving interview with Breege Quinn on the Sean O’Rourke show, Ms McDonald called a press conference at short notice outside her party’s headquarters in Dublin’s Parnell Square.
She was asked to explain the discrepancy between what she had said on Monday versus Tuesday. Did it suggest that Mr Murphy had misled her? "No, he did not. These comments were made more than a decade ago and it was only when I saw the (BBC) Spotlight programme that I had the full content of what was said," she told journalists.
"It was an honest mistake on my part. My recollection had been that the commentary had been about criminality up and around the border region, smuggling and so on which is a reality. I had not realised that the remarks were so pointed."
Ms McDonald appeared to have been referencing her recollection of what was said at the time of the BBC documentary, which she points out is more than ten years ago, rather than referencing what was said in her conversation with Mr Murphy that so reassured her that he had not made the comments about Mr Quinn.
She has not addressed when she had that particular conversation with Mr Murphy which she referred to in the Dobson interview, in which it was made "very clear" that he never said those things about Paul Quinn. Nor has she answered when it was that she watched back that BBC programme – the viewing of which, she says, resulted in her accepting what Breege Quinn has been saying for years. These are serious questions for the party at a crucial time in the campaign.
The Fianna Fail leader, Micheal Martin has asked why it has taken 13 years and on the eve of a general election for Ms McDonald to accept what Mr Quinn’s mother has been saying. Sinn Féin supporters on social media have been asking why the issue has become a news story this close to an election.
Mrs Quinn argues that she has been speaking about this for more than a decade and it is not the case that she is just raising it now.
There is a reality that the record, the reliability and many other qualities of a party leader will come under scrutiny during the course of an election campaign where there is intense political competition not to mind numerous interviews and debates.
Such scrutiny applies to any leader, in any campaign, but is usually relative to their chance of getting in to power.
There are questions around whether this controversy will halt the march of Sinn Féin which has been enjoying a successful election campaign and is leading in the polls.
This could largely hinge on whether people view this as an issue relating to Sinn Féin’s past and whether they are minded to move on from that past as something they can live with.
Or, whether voters will see the complete about-turn in Ms McDonald’s accounts of events as an issue for the present. To the extent that people are voting on what role they would like to see Sinn Féin play in the next Dáil or indeed the next Government, will they see this as an issue of trust and leadership?
Younger voters –among whom support for Sinn Féin is strongest – are motivated by issues rather than party politics. Will they use their vote on single issues such as housing – something they trust Sinn Féin more than any other party according to the Business Post Red C poll - and disregard all other issues which are not relevant to their own lives?
In the last phase of the campaign, other parties said they were not surprised by the youth support for Sinn Féin but were taken aback by older, more traditional and conservative voters who were talking about Sinn Féin on the doorsteps (maybe prompted by it being out of the traps first on the pension controversy.)
Fine Gael and Fianna Fáil felt that this support could be clawed back. Their efforts to do so might be easier on the back of this controversy.
Whatever the impact will be we will know on Sunday.
But there is no doubt that the party which has had a hugely successful general election campaign to this point would prefer not to be in this position: answering uncomfortable questions and having a spotlight shone on its leadership as the penultimate day of this election campaign approaches.