Bertie Ahern can enjoy good cheer this Christmas knowing that he and his party will remember 1998 as the year when so many records were broken.

The high points of the year were the signing of the Belfast Agreement in April and the introduction of a reforming Budget this month which, taken together, have transformed the political landscape in the Republic.

Despite the magnitude of these achievements, however, there is a detectable edginess about the Taoiseach and his party as they savour their public successes. Things are so good, sources say, they can only get worse.

The first minority Coalition is as secure as any government could be in circumstances where it is depending on the support of four different Independents. Yet, notes of tension have crept into the political relationship in the last couple of months since the inimitable Jackie Healy-Rae stole a march on his colleagues with his claim to have retained Kerry as an Objective 1 region.

His apparent success at redrawing the regional map of Ireland has introduced a new factor into the relationship between the Independent TDs and the Government. For, instead of seeking individual concessions to suit their own constituencies, the four TDs are now looking over their shoulders and seeking parity of treatment with each other. This pattern, if continued, could bring instability to the Government, though not one of the Independents wants to precipitate a general election.

The Taoiseach and his party achieved the highest poll ratings in 1998 since the introduction of opinion polls 25 years ago. But few in Fianna Fail, least of all Mr Ahern, believe these percentages will produce electoral results.

The 1998 opinion polls show Mr Ahern is more popular than his predecessor, Jack Lynch, the last Taoiseach to win an overall majority 21 years ago. But these findings have not been replicated in the three by-elections fought by Fianna Fail in government over the last 18 months. The party was stunned, in fact, that its first preference vote dropped from 42.62 per cent in 1997 to 29.43 per cent in the Cork South Central by-election.

The failure so far to translate popularity into votes is the main reason the Taoiseach and his senior strategists are setting such high store on the local elections on Friday, June 11th, next year. Fianna Fail won 357 out of the 883 seats in the last local elections to county councils and borough councils in 1991. It then achieved 37.9 per cent of the first preference vote.

The measure by which that 37.9 per cent share of the vote can be increased in the local elections will determine the party's strategy in the next general election. Fianna Fail sources are confident the party can win extra seats, but the real indicator of their fortune will be the extent to which they surpass their 39.3 per cent share in last year's general election. Mindful that elections are the only real polls in Fianna Fail, the local results next year will dictate whether the party should aim for an overall majority or a big or small coalition partner, in the next general election.

THE real edginess in Fianna Fail at the turn of such a successful year centres on two unplanned events. Despite their faith in their leader, there is a fear about the fall-out from the two tribunals, Moriarty and Flood. There is an uneasiness about the frequency with which Mr Ahern talks about codes of ethical conduct as if the past could catch up with their future.

This theory was put to the test on the latest Haughey controversy when Mr Ahern's handling of the decision by his brother-in-law, Mr Ronan Kelly, to reduce the former Taoiseach's tax bill to zero, was seen as less than sure-footed by his own party.

There is also a tangible unease of another kind over the Taoiseach's public statements about his private life.

At the end of the year, however, two achievements will be accorded historic status among routine events of politics. The first, needless to say, is the unique role played by Mr Ahern in negotiating the Belfast Agreement. The implementation of the accord was further strengthened by the pre-Christmas agreement on the North-South dimensions. Northern issues will take up equal time and effort in 1999. Indeed, with the slow pace of developments it will be interesting to see whether the contingent changes in Articles 2 and 3 of the Constitution will be made in May.

The second achievement, more surprising on a smaller scale, was the Budget. The decision to perform a major restructuring of the taxation system by introducing tax credits will stand to the credit of Charlie McCreevy for years to come. The changes could only have been made at a time when the Exchequer was flush with cash. The Budget was a remarkable U-turn on tax policy.

The Belfast Agreement and the Budget have brought about a consensus on all the major issues in Irish politics. The space for other parties to assert separate identities - Fine Gael, Progressive Democrats, the new Left - has been squeezed by Fianna Fail.