They stayed onside with a turbulent electorate and on Friday took advantage of a near perfect storm to sail to a resounding victory.
More people voted.
An angry electorate had already vented their spleen in June’s local and European elections. And the cities and rural areas for once spoke with one voice.
Consistently one in every five voters changed their minds. In some of the most sceptical areas last year the shift was even greater.
And, in regions suffering the worst in terms of collapsing house prices and job losses, people turned to the European Union for security.
Yes campaigners could not have hoped for a better outcome.
Turnout was a particularly significant factor.
Almost 200,000 more people came out to vote last Friday compared with June 2008.
In the first referendum the difference between victory and defeat was 109,964 votes – even if the No vote held up, with the addition of hoards of pro-Lisbon voters the Yes side would still have had enough to win.
However, the Yes side did more than that. They convinced 267,809 people to change their minds.
And any suggestion the No side had gained traction on the employment issue was glaringly disproved. There was no better example than Limerick.
Here the loss of 2,400 jobs at Dell had been stoked by anti-Lisbon campaigners after it emerged the company was getting €54 million from the Polish government to relocate its production facility to eastern Europe.
However, a visit to Limerick by European Commission president Jose Manuel Barroso in September, when he announced a €14.8m economic support package for the city, was enough to counter this.
Just over 21% of people in Limerick East changed sides and Limerick West, which begins just over a mile from the Dell plant, recorded the largest swing in the country at 24.7%.
At the same time the commuter belt around Dublin, where the value of people’s homes has fallen dramatically and cases of negative equity are most concentrated, residents did not risk falling out with Europe for a second time.
Meath West, Kildare South, Wicklow, Louth, Longford-Westmeath all dropped their initial reservations and voted Yes this time.
The unpredictable population of Dublin ignored its flirtation with the anti-Lisbon set. Apart from the consistently pro-European neighbourhoods in the southside, in June, Dubliners voted to send Joe Higgins to Brussels as their MEP.
Five years earlier they elected Sinn Féin’s Mary Lou McDonald to the same post.
But on Friday, 795,126 voters helped dispel any suggestion of manifest Euroscepticism.
In the more hostile constituency of Dublin South West almost one in four people moved from voting against Lisbon to backing it this time.
Dublin West, where Mr Higgins shares a hunting ground with Finance Minister Brian Lenihan, had a higher Yes vote than the national average with a 68.5% vote in favour of the treaty.
And despite worries of Lisbon fatigue, the figures revealed a remarkable enthusiasm among people to come out to have their say.
Dublin South and Dublin Central had by-elections for crucial Dáil seats in June on the same day as local and European ballots.
But in Dublin South more than 6,000 more people voted in the referendum than had turned up for the by-election.
An additional 1,700 people went to polling stations in Dublin Central. And together they were eager to make a clear distinction between national politics and the Lisbon Treaty.
After emphatically backing independent candidate Maureen O’Sullivan in June the Dublin Central electorate did not respond to her request to bring down the treaty and changed sides by a large margin.
The fact that there was a recent by-election appeared to be a boost to the Yes camp, with both areas suggesting people availed of the opportunity to kick the Government in the June by-elections. The swing in both constituencies was just above 18%.
It bordered on group-think in Dublin South where 81.7% of voters supported the treaty – the highest in the country and marginally ahead of its neighbouring constituency of Dun Laoghaire.
But the swing trends embarrassed the Government leaders.
The Taoiseach’s constituency of Laois-Offaly had among the lowest turnaround figures.
The shift in the public mood failed to resonate most in Tánaiste Mary Coughlan’s home county of Donegal.
There was just a 13% turnaround in both Donegal South West and Donegal North East, they were the only two constituencies to reject the referendum on Friday.
This reversed a trend right down the western seaboard where an above- average number of people switched sides.
By contrast Foreign Affairs Minister Micheál Martin can point to four out of five Cork constituencies making the top 10 turnaround table.
And in terms of Dáil bragging rights, Mayo, the home of Fine Gael leader Enda Kenny, was fifth highest in the shifting stakes. And Labour Party leader Eamon Gilmore had the second highest Yes vote in his constituency.