Leading article: An election that may mark the end of an era

A political upheaval in Ireland has only just begun following the resignation of Brian Cowen as leader of the country's ruling party. Fianna Fail is no ordinary political party. Claiming the mantle of the 1916 Easter Rising, it has dominated the political landscape since the 1930s, providing Ireland with a succession of leaders from Eamon De Valera to Bertie Ahern.

Now the party's very survival is in doubt. When Ireland goes to the polls in the next few weeks, Fianna Fail faces electoral annihilation at the hands of voters enraged by the mishandling of the golden 1990s.

For the main opposition Fine Gael and Labour parties, it may be a case of be careful of what you wish for. This is because it is not certain that they will be the sole beneficiaries of Fianna Fail's probable downfall. Circling the tent of Ireland's old established partiesis Sinn Fein, which sees the present political and economic turmoil in the Republic asthe perfect opportunity to secure a long-sought breakthrough.

Here in Britain we tend to see Sinn Fein from the perspective of Northern Ireland, judging its policies principally in terms of their impact on the peace process and forgetting the rest of its political agenda. In fact, Sinn Fein has been quietly building up strength in the Republic in recent years, trading mainly on the grudge votes of those who felt left behind in the boom years. Now it could emerge as a kingmaker if – as seems likely – it makes off with a large slice of the Fianna Fail electorate.

A political shake-up on this scale in Ireland could be highly destabilising if the result is the overall fragmentation of the electorate and a leakage of votes of away from traditional centrist parties towards the hard left and ultranationalists – all united around policies of economic as well as political nationalism, complete with tariff walls and some archaic-sounding ideas about regaining economic "independence". Ireland's voters may yet spurn these siren voices. But if they do not, it could be harbinger of future political developments in other troubled economies of the European Union.