Adams/McGuinness are very able people and seem to have a long term vision of Sinn Fein as an all-Ireland, nationalist but progressive political force.  I do not underestimate their achievement in weaning Sinn Fein away from the hard men of the physical force tradition and negotiating successfully with hardline Loyalists who basically don't want to talk to them anyway.

Most southern politicians can only dream at an achievement like that and are political spoilt children who have inherited their positions of power by comparison. However SF will also seek to hoover up votes wherever they can and my sense is that virtually all of the 30%+ hard no vote in the EU referenda is up for grabs as all the other parties are v. pro-EU.

So SF will at least have to pander to the hard-line Nationalist, xenophobic, and atavistic vote even if they end up implementing more traditional left wing policies.  They will, of course, not oppose the EU per se - just our current neo-lib model of it - so I do not necessarily have a problem with that.

However I see a more tough minded and less fawning approach to the EU in the future - and great difficulty in passing another EU related referendum unless it is clearly in our national interest.  The major change will be that Sinn Fein - if they lead the opposition - will almost have the power of veto on any new such Treaty, and Merkel will find that Adams is a much tougher negotiator than she has ever had to deal with in the past.  Think of it as requiring Merkel to negotiate with Die Linke Partei in Germany to form a Government...

Index of Frank's Diaries