By Shane Harrison BBC Dublin correspondent

Irish MPs return to the Dail (parliament) on Wednesday afternoon for what is expected to be a short session before Prime Minister Bertie Ahern calls a General Election.

When Mr Ahern came to power in 1997, he promised his coalition government with the Progressive Democrats would last five years. Few believed him.

After all, his Fianna Fail party, more used to single party administrations, hardly had a good record of sharing power. But that has now changed.

Bertie Ahern's party has been in a coalition government since 1997

As for his achievements, Mr Ahern can point to the Good Friday Agreement that has brought some form of stability to Northern Ireland and to the Republic of Ireland's booming economy.

But the opposition parties say Fianna Fail remains an "ethically-challenged party".

Six of those 77 TDs (MPs) elected five years ago have suffered some form of humiliation or forced resignation.

Most because of tax-evasion-related activity in the 1980s. But the whiff of scandal remains.

Sinn Fein has a different whiff to deal with - that of cordite. Party President Gerry Adams claims there are "no organic links" between Sinn Fein and the IRA.

Mr Ahern disagrees and says the continued existence of the IRA means Sinn Fein cannot, because of Article 15 of the Irish Constitution, be a coalition partner.

"Hypocrisy", replies Sinn Fein. "If it's okay for us to be in government in Northern Ireland with the Ulster Unionists why not with Fianna Fail in the Republic?"

The party believes the constitutional argument is nonsense.

Gerry Adams: "No organic links" between Sinn Fein and IRA

It is a view supported by at least one academic lawyer, Gerard Hogan from Trinity College Dublin.

He told the BBC Northern Ireland Hearts and Minds programme last week that while there were sound political reasons for excluding government, there was no legal or constitutional ground.

Sinn Fein has one TD at the moment. It hopes to come back with three but the bookies reckon seven.

At stake are the wastelands of opposition or the lush plains of political power

Opinion polls suggest that Mr Ahern is much more popular than Michael Noonan, the leader of the main opposition party Fine Gael.

Indeed, if the same polls are to be believed, the only question that needs answering is: Who will Fianna Fail be back in government with?

Will it be the Progressive Democrats, Labour, the Greens or independents? Or is it conceivable that there will be a single party government?

The phrase "single party government" for many Fianna Fail leaders is the hidden desire that dare not be spoken of, at least, in public.

That is just in case the electorate gets scared of trusting the party with an overall majority, given its ethical record.

But Fianna Fail and the other parties know that very soon the most important court they will soon face, that of public opinion and the electorate, will soon decide on their fate.

At stake, the wastelands of opposition or the lush plains of political power.