Mr Thomas Gildea, who represents Donegal South West, appears to be the most vulnerable of the Independents supporting the Government to a strong challenge for his seat at the next election.
However, nobody in the constituency is ready to write his political obituary. His election in 1997 caused a sensation, and for a time Mr Gildea was a lowkey figure in Leinster House.
He later pledged his conditional support for the Government and enjoys access to the Taoiseach and his Ministers on constituency matters.
Like the other three Independents, he has become a national figure through extensive media coverage.
A Glenties-based farmer, Mr Gildea broke the Fianna Fail stranglehold on the constituency, which saw it returning two FF TDs and one FG TD at every election since it was set up in 1937. His fellow TDs are Ms Mary Coughlan (FF) and Mr Dinny McGinley (FG).
Fianna Fail has yet to select a running mate for Ms Coughlan, and there is local speculation that the Connacht-Ulster MEP, Mr Pat "the Cope" Gallagher, who was formerly a TD for Donegal South West, will stand for the Dail again and resign his European seat if elected. If he does, he would pose a formidable threat to Mr Gildea.
Another possible FF candidate is Senator Enda Bonner, from Dungloe, who ran in 1997, when he polled 5,742 first preferences, only 150 ahead of Mr Gildea, who overtook him in transfers in later counts. Mr Bonner was subsequently appointed to the Seanad by the Taoiseach, Mr Ahern.
In 1997 the Fianna Fail vote dropped 10.64 per cent to 38 per cent in Donegal South West.
Mr Gildea was elected on the issue of TV deflectors, which was resolved after protracted negotiations with the Government, resulting in a licensing regime. He claims that his support for the Government has yielded £31 million worth of constituency projects.
He contested the 1999 local election, taking a seat on the final count without reaching the quota in the Glenties electoral area. He had polled 1,000 first preferences, which put him in fifth position after the first count.
Mr Harry Blaney, who represents Donegal North East, remains undecided as to whether he will stand again. He told The Irish Times: "The selection of a candidate will be a matter for the organisation, and a decision will probably be made when the election is called."
Mr Blaney shares the constituency with two Fianna Fail TDs, the Minister for Tourism, Sport and Recreation, Dr McDaid, and Ms Cecilia Keaveney.
In the last election, Mr Blaney polled 7,484 first preferences, second to the poll-topper Ms Keaveney, who had 8,317, but ahead of Dr McDaid, who had 6,538. Dr McDaid held his seat by defeating the veteran Fine Gael TD, Mr Paddy Harte, by 515 votes.
Should Mr Blaney stand down, his organisation has a strong candidate in his son, Mr Niall Blaney. He was elected to Donegal County Council in the three-seat Milford area, topping the poll with 2,001 first preferences.
Fine Gael is making a determined effort to win back the seat held by Mr Harte since 1961 until the last election, but the local organisation is dogged by infighting.
A selection convention chose Mr Bernard McGuinness from Culdaff, a businessman and Donegal county councillor since 1979. Mr Sean Moloney, a Letterkenny county councillor and psychiatric nurse, was added to the ticket by the party national executive. Mr Moloney is a former Labour senator.
Ms Mildred Fox, who represents Wicklow, was thought to be vulnerable at the last election, but managed to take the fifth and final seat. She edged out the long-serving Labour TD, Mr Liam Kavanagh, by 277 votes. Her status in the Dail has increased her profile and constituency clout.
Labour has a seat in the constituency since the merger with Democratic Left, whose Wicklow TD, Ms Liz McManus, took the third seat in 1997. The others are held by Fianna Fail's Mr Joe Jacob, Minister of State for Public Enterprise, and Mr Dick Roche, and Fine Gael's Mr Billy Timmins.
Ms Fox and her colleagues are keeping a keen eye on the future electoral intentions of the Ark low-based Independent county councillor, Mr Nicky Kelly, who polled almost 5,000 first preferences in the last election.
In the 1999 local elections Mr Kelly secured 1.4 quotas in the Arklow electoral area, making him a strong contender for a Dail seat. He confirmed to The Irish Times that he has been approached by the political parties, adding: "I will meet my supporters throughout the constituency in the new year and decide what is best for the county."
Mr Jackie Healy-Rae, who represents Kerry South, has the strongest electoral base of the four. A long-serving Fianna Fail activist, he broke with the party before the last election after he failed to get a nomination.
He stood as an Independent and topped the poll with 20.34 per cent of the vote, 16 votes ahead of Mr John O'Donoghue, the Fianna Fail Minister for Justice. Mr HealyRae took the seat at the expense of his old party and has firmly ruled out returning to the fold.
The third seat is held by Labour's Ms Breeda Moynihan-Cronin. There is likely to be no change in the constituency lineup, and the main interest will be on whether Mr Healy-Rae or Mr O'Donoghue tops the poll.
Fine Gael, which once had a seat in the constituency, and a comfortable quota, has yet to choose its candidates. There are big divisions within the local organisation.