The emergence of Labour's senior figure, Mr Michael D. Higgins, and the Kerry TD, Ms Breda Moynihan-Cronin, as Mr Brendan Howlin's nominators in the leadership contest has boosted his campaign to succeed Mr Dick Spring.
As nominations closed at 5 p.m. yesterday, speculation intensified that the former leader may vote for Mr Howlin after Ms Moynihan-Cronin, who represents South Kerry, seconded the declaration.
The other contender, Mr Ruairi Quinn, was nominated by Dublin deputies, Mr Tommy Broughan and Mr Derek McDowell.
With the contest too close to call, the final result lies in a hands of a small group of voters from Labour's governing body, the General Council. Yesterday's nominations have pointed up a distinct Dublin-rural fault line in terms of the Parliamentary Labour Party's voting intentions. Both Mr Howlin's nominators came from outside Dublin, while Mr Quinn's two nominators came from within his urban power base.
Senior sources calculated that Mr Howlin has a slight majority of support within the Parliamentary Labour Party at this point, but the issue will be ultimately decided by non-Oireachtas members of the 64-strong voting college. Thirty-three votes are needed to win.
A number of constituency council meetings are still being held to determine how the PLP and general council members should cast their vote in Thursday's election.
Both camps were last night claiming that support was holding up well in favour of their respective candidates.
While sources among Mr Quinn's supporters claimed that votes committed to him would make him the new leader, Mr Howlin predicted that he would be victor. "It will be close and I expect an overall majority on the day. I'm within striking distance of an overall majority," Mr Howlin said.
According to Mr Quinn, it now appears he can win the contest, but it is not over until the last vote is cast.
The declared backing of a Labour party veteran like Mr Higgins has augmented Mr Howlin's efforts and brought to five the number of TDs openly supporting him. It also comes in the wake of an Irish Independent opinion poll which showed that a clear majority of the electorate supported Mr Quinn. Dismissing the possibility that the 64 voters would be influenced by opinion polls, Mr Howlin said this would be "a very considered, thoughtful process".
"Any uncertain voters would look at the opinion poll and say that what the public wants should not be disregarded," one source said.
Meanwhile, in a three-page letter to voters, Mr Howlin made a strong pitch for the post, promising full accessibility to his leadership and stressing his determination to run an inclusive party.
Covering a wide range of issues from protection for workers rights to tackling urban decay, Mr Howlin also spoke of the need to respond to major problems like drugs and crime.
He envisaged enhanced powers for local government and said he would spend much time, if elected leader, travelling the State in the reorganisation of the party.
In a similar pitch, Mr Quinn wrote to voters pointing out that he was a campaigning politician and outlining his plans for a renewed Labour.
He also sent to the PLP and General Council copies of articles he had written assessing Ireland's future, economically and socially, and looking at the future of socialism.