Along with the rise of Fine Gael and the apparently growing credibility of Enda Kenny, the other big story of this election campaign has been this implosion of Labour.
So why has this implosion happened? The question should be, perhaps, has it happened at all.
At 20%, Labour would double its first preference vote in the 2007 general election, and would just about exceed its historic high of the 'Spring Tide' election of 1992 (which itself entailed a doubling of its vote in the previous election).
Its vote in the 2007 election was disappointing when compared with the trends in the polls over the preceding Dáil terms. Most polls had predicted a higher vote, and Labour got an average of 14% in TNS/MRBI polls over that cycle.
Following the 2007 election, Labour's support in the opinion polls remained in the low teens for most of 2007 and 2008. It started to climb in late 2008, reaching 23% (in a TNS/MRBI poll) in May 2009 – but a month later, in the 2009 local elections, Labour won just 14.7% of the first preference vote.
Yet immediately after that, Labour's poll ratings were in the high teens (according to Red C) and early-to-mid twenties (according to TNS/MRBI). (Red C has consistently placed Labour between five and seven percentage points below their TNS/MRBI rating.)
In other words, Labour's poll ratings appear to consistently give an inflated idea of their electoral strength; and Red C's poll results have tended to be closer to Labour's actual strength. Historically, that strength has varied around the ten per cent mark, with the striking exception of 1992.
That makes the prospect of Labour securing a vote approaching 20% (17% according to the latest Red C poll) a dramatic improvement for Labour. And, building on the 2009 local election results, it would mark a consolidation of Labour at a significantly higher level than before.
In September last year, Labour's ratings soared into the low thirties, according to TNS/MRBI (though Red C never placed them above 27%). Political debate turned to the question of Gilmore as a possible Taoiseach; following the three-way debates in the UK election, it became inevitable that he would have to be included in any leaders' debate here.
But talk of Gilmore as Taoiseach was always off the mark, and for more than the simply statistical reasons cited above.
Polls taken outside of a campaign tend to respond to news events or issues. But people don't vote for issues – they vote for people. To translate a poll rating into electoral success requires candidates. And Labour has not had the quantity, quality or spread of candidates to make that a reality. (This, of course, could be taken as an indictment of the leadership.)
Take the example of Dublin Central (where I live). It is one of the most left-wing constituencies in the country – though this was severely distorted by the Bertie effect, which saw Ahern, portraying himself as a "socialist" and local patron, help ensure a 41% first preference share for Fianna Fáil in 2007. In the 2009 by-election following the death of Tony Gregory, left-wing candidates secured approximately 60 per cent of the vote.
Were Labour ever to have a prospect of leading a government, this is a constituency in which they would need to be in the running for two seats. Yet the current election sees the incumbent, Joe Costello, now 65 years old, running a low-profile campaign, with a running-mate, Aine Clancy, who has no media profile at all (and almost no online presence at all, bar a few tweets) and little profile across the constituency. In the by-election, which could clearly have been an opportunity to build a profile for a future running mate for Costello, Labour parachuted in Ivana Bacik, now running in Dun Laoghaire.
There is a further reason that the 'Gilmore for Taoiseach' slogans were never credible, and that the thirtysomething poll ratings should have been treated with severe scepticism. Labour is left wing(ish); and Ireland isn't.
Unlike the UK, where New Labour theoretically blazed a trail for Irish Labour to follow, Ireland has never had a government led by anything other than a conservative. (The closest to a left-liberal leadership the country has come was probably Garret Fitzgerald.)
Eamon Gilmore was very successful at reflecting and channelling the public response to Fianna Fáil's mismanagement of the economy. His two standout moments in the last Dáil were when he called on John O'Donoghue to resign as Ceann Comhairle, and when he accused Brian Cowen of "economic treason". Both were rhetorically effective; neither was justified on the strict merits of the argument.
But there was little evidence that these poll ratings reflected the kind of changing ideological or policy perspective amongst the public that would be needed to convert them into seats in an election. Instead, other poll results suggested an underlying conservatism in the electorate: the consistent popularity of Brian Lenihan through to late 2010; majority support for the EU/IMF 'bailout' deal (at 51%); and the ongoing, high personal approval ratings for Michael Martin.
With a strong performance in last night's leaders' debate, and a more coherent message from Gilmore about the need for Labour to ensure 'balance' and 'fairness' in government, it may be that the news cycle of the Labour 'implosion' story has been broken. But that story in itself did huge damage to Labour in the first weeks of the campaign, and allowed Fine Gael to acquire an apparently unstoppable momentum.
A more nuanced and less sensationalist approach from the news media might have given the story less credence in the first place. But had Labour refused to be persuaded by the earlier stories of 'Gilmore for Taoiseach'; had it concentrated on building support for its policies and ideology, instead of playing 'presidential' style politics built on a rhetoric of protest, there would have been less to hook the story of its 'implosion' on.
Eamon Gilmore has made no secret of his keenness to get into government. But the longue durée suggests they have a real possibility of becoming a stronger force in Irish politics – if they further consolidate baseline Labour support, and (this is crucial) build a new network of credible candidates. That may be work that is better done in opposition.