There are wide differences between Fianna Fáil and Sinn Féin on policy, both in the details of the pledges by the parties on individual issues and on overarching economic matters.

Taxation and wider economic policy is the most obvious area, but on a whole series of issues – from housing to healthcare to climate change – there are very substantial policy differences between the two manifestos.

The big question is if these policy differences could be overcome to agree a programme for government.

They are certainly very substantial. But coalition negotiations have rarely if ever broken down over policy. Once parties embark on detailed negotiations, exchanging documents and draft programmes for government, they have tended to end up with an agreement, and proceed to a coalition government.

So policy differences are important, but they have tended not to prove insurmountable.

Some people in Fianna Fáil say yes, the differences are huge, but isn’t that what coalitions are about – agreeing a compromise policy platform that both parties could live with?

Above perhaps any other party Fianna Fáil has been flexible in agreeing coalitions with other parties

They [always] point out that Fianna Fáil used to say it would never go into coalition with anyone right before it went into coalition with the Progressive Democrats. Coalitions with Labour, the Progressive Democrats (twice more) and the Greens followed.

And then the party designed and implemented the confidence and supply agreement with Fine Gael in preference to the grand coalition offered by Enda Kenny in 2016. So above perhaps any other party Fianna Fáil has been flexible in agreeing coalitions with other parties.

But the differences with Sinn Féin are not just about policy; they may not even be principally about policy. There is a widespread belief in Fianna Fáil – shared by many though not all its TDs – that Sinn Féin is not a sufficiently “normal democratic” party for Fianna Fáil to share power with.

Culture

This view was extensively set out by party leader Micheál Martin and other senior party figures during the election campaign, and centres on not just the history but also the present culture of Sinn Féin.

Here’s what Martin told The Irish Times in an interview during the campaign: “Sinn Féin’s justification for the IRA’s war is a continuing one. There never has really been any contrition and also to a large extent they want to shove down the throats of a new generation a narrative about the atrocities there were carried out which in my view serves to poison future generations.”

Asked if he wanted Sinn Féin to admit it was wrong, he said: “Yes, I do want them to admit they were wrong, and, as Seamus Mallon said, to admit the IRA’s campaign was 40 years of failure.

“In the peace process we all had to make compromises in order to achieve the peace, but Sinn Féin need to come some distance too and they haven’t.”

Martin has also set his face firmly against the demands by Sinn Féin that the united Ireland agenda should be top of the new government’s priorities

Martin was also Sinn Féin’s fiercest critic when the family of Paul Quinn, who was murdered in Armagh in 2007, sought an apology from Sinn Féin’s Northern finance minister Conor Murphy for linking Mr Quinn, who was beaten to death by a gang allegedly connected to the local IRA, to crime.

“The Paul Quinn murder stands out,” he says. “But the omerta that follows it – that people are so afraid and so intimidated by that organisation that they won’t engage with the police.”

United Ireland agenda

This is what makes it so difficult for Martin to effect a U-turn if that is what he contemplates. He accepts that his greatest objections to having Sinn Féin in a coalition government with his party are the “moral” questions, as he has termed them, rather than his opposition to Sinn Féin’s economic policies. “That’s fair enough,” he said.

Martin has also set his face firmly against the demands by Sinn Féin that the united Ireland agenda should be top of the new government’s priorities.

Mary Lou McDonald has said there has to be a Border poll within five years. Although this is a decision for the British government under the Belfast Agreement, any government that included Sinn Féin would insist that concrete measures – such as a white paper and a citizens’ assembly – to prepare for Irish unity would begin immediately. The official position of the Irish government towards the North would shift dramatically.

The mood in Fianna Fáil on the subject is febrile. Many TDs are vehemently opposed to the very idea of coalition with Sinn Féin, but some of them are also filled with horror at the idea of a deal with Fine Gael.

The party could be forced to choose between the lesser of these two evils.