FitzGerald exit leaves new Irish premier without opposition ally. Haughey's tough plan for economy faces rough road

Charles Haughey is known in Dublin as the great survivor of Irish politics. By the slimmest margin possible, the Irish Parliament on Tuesday elected him prime minister for the third time when the speaker of the D'ail cast a tie-splitting vote. His task may well be made more difficult by yesterday's resignation of Garret FitzGerald, the outgoing premier, as leader of the main opposition party, Fine Gael.

Dr. FitzGerald had pledged his party's support to Mr. Haughey for any tough economic measures necessary to deal with Ireland's chronic economic problems. It is unlikely that the new premier will be able to depend on that kind of cooperation from other politicians in the Irish Parliament who see it as their role to oppose him.

The new government's most urgent task is introducing a budget to start the process of tackling Ireland's economic difficulties. These include a huge national debt, an unemployment rate of 20 percent (which is driving thousands of Irish youngpeople to Britain and the United States to seek work), and the need to impose tough cuts on public spending.

Even if Haughey receives the support of the two main conservative parties, Fine Gael and the Progressive Democrats, to get his budget through Parliament next month, he knows that this cooperation will not extend to other areas of legislation. His Fianna Fail party is traditionally populist in its attitudes, and if he does introduce tough economic measures he is likely to alienate large sections of the party's vital working class.

In theory, Haughey could survive by juggling the parliamentary arithmetic on a day-to-day basis, seeking the support of the right for some of his policies and of the left for others. In practice, that would impose an impossible strain on ministers attempting to put through a coherent legislative program. Besides, Haughey needs to convince the public, at home and abroad, that he can provide stable government.

Apart from the economy, the other issue on which his opponents will be watching Haughey closely is Northern Ireland. In particular, they will be monitoring his attitudes to the Anglo-Irish agreement, which FitzGerald signed with British Prime Minister Margaret Thatcher in November 1985.

Haughey has the reputation of being more militantly nationalist (favoring a united Ireland) than his predecessor. When he was leader of the opposition, he expressed grave reservations about the accord, which provides that, in exchange for an Irish say in the running of the North, there will be no demand to change its constitutional status as part of Great Britain until a majority wants it. Haughey maintains that the accord threatened the Irish Republic's traditional aspiration, enshrined in the Constitution, to the reunification of the country.

Yet Haughey has gone quite a long way to try to reassure the British about his own intentions. He has said he will continue to back the agreement and has put one of his most trusted lieutenants, Brian Lenihan, into the Department of Foreign Affairs to supervise the Irish role. Another, perhaps more pressing, reason why he is unlikely to do anything to harm the Anglo-Irish agreement is that he knows the overwhelming majority of Irish people support it.