IRELAND may soon become ungovernable. With the political dominance of the two Civil War parties in permanent decline and without any of the mechanisms that other countries employ to favour stable government, the splintering of the vote is pointing ominously towards Italian-style political chaos. Short-lived and unstable multi-member coalitions, incapable of providing effective government, are looking increasingly likely to be the new normal in Irish politics.

It is a quarter of century since the last single-party government held office and it is now almost inconceivable that any one party will ever govern alone. That is not because of short or even medium-term political factors, but in keeping with a profound underlying trend.

Over the past three decades the combined share of the two Civil War parties' first preference vote has been in decline. From 80 per cent and more in the decades up to the early Eighties, the Fianna Fail-Fine Gael share of the vote has been shrinking. In 2011 it plummeted to less than 54 per cent.

This trend appeared to bottom out during the Celtic Tiger period, but the underlying pattern was merely obscured. During the days of the boom and bubble, Fianna Fail could use surging tax revenues to please everyone. Its support was as artificially inflated as the property market.

When the bubble burst, Fianna Fail's did too, and the once-dominant party's support fell as fast as the tax revenues it used to buy votes in the good times. While the party is almost certain to recover from its 2011 nadir, it is very unlikely ever to return to the levels it enjoyed in the Nineties and Noughties, when it was winning 40 per cent of the vote.

There is nothing surprising about all of this. Political fragmentation is the norm in European democracies, particularly in countries with proportional representation voting systems. A number of factors cause this, and most of those factors are present in Ireland.

The first is diversity. As societies become more diverse, so too do voting patterns. Niche parties proliferate. Those advocating nationalism, economic liberalism, social conservatism, opposition to immigration, regionalism and environmentalism are just some of the niche parties which exist across Europe.

A second factor driving fragmentation is declining loyalty to political parties. The numbers of card-carrying members of parties is falling almost everywhere and a growing share of electorates in mature democracies are willing to consider voting for a range of parties come election time. This may be related to higher levels of education which lead voters to be more confident in their own analyses of politics, and less willing to follow politicians' leads.

One of the less welcome by-products of the 'death of deference' is a greater hostility and cynicism towards politics in general. A 'plague on all their houses' attitude is increasingly common. Opinion surveys show that faith in political parties is falling and election results in some countries show rising support for incoherent populist parties and even anti-politics groupings, such as Italy's 'Five Star' movement.

In Ireland, anti-party sentiment is particularly strong. Surveys from the Comparative Study of Electoral Systems showed 49 per cent of people expressed hostility to political parties in general, a level almost twice that of the second-placed country, Belgium (at 26 per cent).

There has been no little discussion of how difficult it will be to form a government if, at the next general election, voting reflects recent years' opinion polls. But the focus on the composition of the next Dail may serve to obscure the scale of the transformation in Irish politics and its consequences far into the future.

The potential for a transformation to ungovernability is real because a splintering of the vote is likely to have a greater impact on government formation and stability in Ireland than in most other countries. There are a number of reasons for this.

The first is the phenomenon of independent TDs. Liam Weeks, a University College Cork academic, has surveyed 36 rich democracies. In 2013 he found that there were 32 independents in total across all of these countries – and that almost half of them sit in the Dail.

While independents can bring valuable skills and abilities to politics, as many of the current crop in Dail Eireann demonstrate frequently, they make coalition formation more difficult and make governments which depend on them more unstable, as has been seen frequently in Ireland when governments have needed their support to make up the parliamentary numbers.

Another reason fragmentation risks making Ireland ungovernable is that in many other democracies a number of mechanisms exist to limit the effects of vote splintering. Ireland has none.

One commonly used method of limiting the effects of electoral fragmentation on political effectiveness and government stability is voting thresholds for parliamentary representation. From Austria and Belgium to Sweden and Spain, any grouping or individual which fails to win a minimum share of the national vote – usually 3-5 per cent – will not take seats in parliament. Thresholds not only limit the effects of fragmentation; they also lessen it in the first place, because people know that a vote for a tiny party or an independent is a wasted vote.

Another mechanism that some countries use to enhance the stability of government is the fixing of election dates. From the US Congress to the European parliament, terms are set and incumbents cannot trigger a vote at an opportune moment. In the case of countries in which coalitions are the norm, the incentive to pull out is lowered when participants can't collapse a government in the hope that the ensuing election will see their support rise.

The stability-enhancing effective of fixed terms can be seen in our nearest neighbour. An important factor in keeping the governing Conservative-Liberal coalition together was the adoption in 2011 of fixed five-year terms.

If the trends in opinion polls in recent years are reflected in future elections, it will become very difficult for any combination to form workable Dail majorities and even harder to keep them together. The weak and unstable governments of the 1981-82 period, when three elections were held in quick succession, may be what is in store for the future.

Sunday Independent