In the presidential election, Sinn Fein worked on a number of clear assumptions. Though these were well known to its membership and its supporters, they were less apparent to the Irish electorate. The first was its claim to now be one of the main political parties in the State, in contention for the role of main opposition party in place of Fianna Fail.

As such, the party made a second assumption. This was that, as a main political party, it needed to run a candidate for the presidency. It was reinforced in this by the scale of Fianna Fail's collapse in the February general election together with the party's decision not to contest the presidential election. The first was unexpected, the second the result of an understandable loss of confidence combined with colossal debts.

Although the presidential election turned into an unprecedented multi-horse race, the vacuum created by Fianna Fail's self-exclusion was tailor-made for Sinn Fein.

The next assumption concerned the choice of a candidate. The announcement of Martin McGuinness's candidacy was audacious, to say the least. Having no vote himself in the Republic, being a leading member of the Northern Ireland political system and deputy prime minister and belonging to a power-sharing executive there in the making of which he had played a role, these were all ostensibly political assets. With them went a world status, experience of tough campaigning and great skill in handling awkward questions.

Sinn Fein thought this outweighed the negative side. It was wrong. He did not fit. He did not belong. He did not know how to handle the justified outrage of those with loved ones murdered by the organisation he had led.

He overstated the achievement of peace in Northern Ireland. He grossly understated the unwanted legacy of criminality and terrorist carelessness over human life in the Republic. It dogged and haunted his campaign. To a certain extent, it soured the campaigns of others, though not without help from some of them.

What alternative did Sinn Fein have? Obviously, it could have skipped a generation and moved outside the shameful legacy of violence that is so inextricably linked to the name of Martin McGuinness.

Strategically, this would have been clever in two respects: there is the obvious appeal for the next generation in Sinn Fein of moving on from both McGuinness and Gerry Adams; and they are ripe for retirement and need to go soon if the party is to progress organically toward its other important political objective, which is to replace Fianna Fail.

That party is struggling with a similar problem. Its leader, Micheal Martin, belonged far too centrally to the government we have endured for the past 12 years. Fianna Fail is so much in need of rejuvenation that it could not publicly show its face on the hustings during the presidential race. It ended up in a covert operation -- typical of Martin's political style -- and this went horribly wrong.

In real terms, Sinn Fein, despite what seems to me to have been a misjudgment over McGuinness's candidacy, has nevertheless furthered its main and underlying objective, which was to improve its opposition status, strengthening itself on the ground and improving its overall political strength.

IT also seemed to me, during the campaign, that McGuinness, despite the good vote he got in certain parts of the country, lessened the standing of Sinn Fein as it has evolved between the 2007 and 2011 general elections. This has to be assessed in terms of a party that has been seriously in need of better performances on issues such as Europe, the economy, jobs, housing, mortgages and emigration.

Its progress in these areas, dogmatic and blunt, and without much subtlety or innate wisdom, is the right way to be going. This campaign will be looked back on as a churning over of historical questions for which the older generation in Sinn Fein has not worked out any good answers.

The abiding memory for the party will be an unhappy one. This is because it will be clearly remembered how the tragic victims of Provisional IRA murders had the courage and calmness to stand up to McGuinness, question him about the deaths of their loved ones, and find him wanting. They visited on a very hard-boiled character a deserved humiliation about his violent past.

A lot of questions remain as a result of this. They will not go away. McGuinness was unable to answer them during the campaign. He is unable to answer them now and goes back to his political role in Northern Ireland diminished in the eyes of many voters in the Republic.

Sinn Fein and Fianna Fail come out of this presidential election in a changed relationship. In the eyes of many, the most devastating thing the Sinn Fein Party achieved, through McGuinness, was the exposure of Sean Gallagher as a kind of bagman for Fianna Fail, completing a long litany of questions about the 'independence' of a candidate who in all but declared aims, was a Fianna Fail figure. That exposure gave the presidential prize to Michael D Higgins.

Fianna Fail has some explaining to do. Who was involved in Gallagher's strategy and his campaigning?

What happened to the Fianna Fail vote in the councils that endorsed him?

What was said in the higher echelons of the party as the complicity became more and more obvious?