THE posters were still there. "Congratulations on becoming Taoiseach" read one, and "Well done Brian" said another posted on a lamppost.
But the honeymoon was most certainly over in Cowen Country yesterday.
'No' is a dirty word here and it was hard to find anyone who'd publicly admit to ticking that particular box on Thursday.
But tick it they did. Lots of them.
In boxing parlance, it was no more than a technical knockout for the 'Yes' side in Biffo's own backyard -- 56pc to 44pc in favour, but given the national figure, meaningless.
Suddenly, after all the street parties and the homecoming, there were real questions about Mr Cowen's leadership over Lisbon.
It seemed like heresy here, but some brave souls broke cover. "Sure he said he didn't even read the thing himself, I decided on my 'No' there and then," said civil servant Martin Cunningham.
As he filled up at an Esso garage, he added: "How can you seriously expect us to vote for something our own leaders are not bothered to read?"
Fine Gael TD Olwyn Enright kicked off the local recriminations. "The Fianna Fail leadership contest was a huge distraction from Lisbon, taking up a whole lump of time," she said.
Mr Cowen had departed Offaly for Dublin at 7.30am, hopes of him popping in on the Tullamore count later on melting away as the gloomy national trends solidified.
Over at a cavernous former textiles factory on the edge of town, the mood was dark as 53 tellers flipped through 50,000 votes.
The sorting of the 54pc turnout was watched by 30 agitated tallymen and tallywomen, their eyes frantically darting over the little white slips.
The Taoiseach's centre of operations was a nearby trestle table manned by Mr Cowen's constituency secretary Sinead Dooley.
She paced the room, a mobile phone clasped to her ear. The boss rang at least four times within an hour of the counting beginning at 9am.
One by one the Fianna Fail tallymen and women filed across to Ms Dooley bearing the latest figures. They were tapped into a laptop and dispatched to HQ in Dublin.
Things were looking bad. Laois had largely voted 'No', Offaly had gone the other way, helped by Mr Cowen's legendary vote-pulling power.
But taking Cowen Country for granted was simply not an option yesterday and from early morning there was real gloom in the Fianna Fail camp.
Of the 195 ballot boxes, 42 had been cracked open and accounted for by 10.30am.
Clara, Mr Cowen's home town, came through for him.
Turnout was estimated at more than 70pc while one ballot box showed a 73pc 'Yes' vote.
As the black boxes emptied, it was possible to get little snapshots of what was taking place across the Taoiseach's constituency.
Edenderry in Co Offaly showed a remarkable split when a box from the town hall was counted -- 175 'No', 175 'Yes'.
Castletown in Co Laois showed 98 'No' votes and 88 in favour of the treaty. "Must be all the Dubs living there," snorted one observer.
But the town is home to Sean Fleming, Fianna Fail TD and one of Mr Cowen's best friends and supporters.
At 1pm, as the final unofficial tallies confirmed the 'Yes' majority, he admitted the whole document "had been difficult to sell". Mr Cowen said he hadn't read it. Did that help?
Mr Fleming smiled, shrugged and added: "People just found it confusing. The biggest issue really was that so many people stayed away."
As the count wore on, the party troops appeared increasingly shellshocked as bits of information trickled in from beyond the frontiers of Cowen Country.
It was meltdown. Dublin was lost, there was no hope in Cork and even Enda Kenny's fellow Mayo men and women had rejected Lisbon by a mammoth margin.
More rumours abounded -- the German's were going to make a statement denouncing Ireland and French President Nicolas Sarkozy was said to be furious.
'Was it any wonder?' asked Cowen's loyal troops. The whole thing had been ruined by the endless distortion and untruth telling by the 'No' side.
Fianna Fail councillor Danny Owens said he knew one party member who voted 'No' as he didn't want his daughter conscripted into a European army.
"That's the kind of misinformation we were up against," he said, shaking his head.
The party bought lunch for the faithful. Vouchers for a carvery at the Tullamore Court were dished out and Mr Cowen's army filed out to get their free grub. They had delivered Offaly for their boss, but it was cold comfort.
And it was Friday the 13th to boot.
After hours of waiting, the "win" was finally confirmed. It came at 4.55pm when returning officer Verona Lambe took the microphone.
"The result of the referendum is as follows. The valid poll was 56,749. [A total] 31,786 voted for the amendment, 24,963 voted against." There it was then -- 56pc in favour, 44 against. Some Sinn Feiners let out a holler and briefly held aloft a tricolour.
Among Mr Cowen's loyal band there were only long faces.
"At least the weather is good," said one as they left the building in silence.