By Alison Roberts
The debate on the European Constitution began late in Portugal, and so far has focused on the date of any referendum, what question it should ask, and whether one should even be held.
Barroso has spearheaded Portugal's role in the EU
Both main political parties - and most opinion formers - favour the treaty's ratification, despite the flaws many see in it.
However, the referendum process is fraught with complications.
Most Portuguese are instinctively pro-EU, aware of how membership since 1985 entrenched a democracy established barely 30 years ago, after a dictatorship of four decades.
Their europhilia was clear in polls that showed Portugal as the EU member whose citizens most favoured this year's enlargement, despite studies pointing to its being the biggest loser.
This accepting attitude is now tempered by growing unease that voters were never directly consulted on Europe.
Polls show that most do want a say.
"A referendum on the constitutional treaty won't eliminate the democratic deficit in Europe," Luiz Fazenda of the small Left Block told parliament.
"But it gives the sovereign people an opportunity to pronounce on it."
In public, both the right-of-centre Social Democrats, who lead the governing coalition, and the opposition Socialists favour a referendum.
But there is a problem: Portugal's 1976 constitution states that the text of a treaty may not be put to a referendum.
The two possible solutions are to change Portugal's constitution to allow this, or word the referendum question in a way that voters can nevertheless make their views clear.
Pedro Santana has stopped short of scheduling a referendum date
Portugal's directly-elected head of state, Socialist President Jorge Sampaio, has expressed concern that this might result in a confusing question, or uncertainty about the consequences of a 'no' vote, and would not oppose amending the constitution.
An amendment needs a two-thirds parliamentary majority, so the government needs opposition help.
There is some euroscepticism at both ends of the political spectrum.
The Communist Party says the European Constitution moves the EU further away from the people and that a small core of countries will run things.
Communist MEP Ilda Figueireda has called for power to be handed back to national parliaments.
On the right, the Popular Party long opposed European integration, calling instead for closer links with Portugal's former colonies.
But since it entered the governing coalition in 2002 its leader, Deputy Prime Minister Paulo Portas, has been muted on the subject.
That opened up space for former PP leader Manuel Monteiro, who founded a new party.
He warns of a centralised European state, fears for citizens' freedoms and says there is a "tacit accord" between the big parties to scupper a referendum.
That accusation is not so far-fetched, given that they have spent months batting the issue to and fro.
Social Democrats say the referendum question can only be framed once Portugal's constitution is amended, and that the onus is on the Socialists to agree to this.
The Socialists say the government should have thought of that when it was last amended, in April (to clarify the relationship between EU and national laws), so the ball is in the government's court.
In private, each side suggests the other may not want a referendum.
The initial proposal of Josť Manuel Barroso, before he stepped down as prime minister to head the European Commission, was to hold a referendum last 13 June - the day of the European parliamentary elections.
But Portugal's constitution also rules out holding a referendum on an election day. And campaigning would have been tricky, since all eyes were on the European football championship finals that kicked off in Portugal on 12 June.
Mr Barroso at least pledged to hold a referendum, but his successor, Pedro Santana Lopes, has been vaguer.
His government's programme, unveiled in July, refers to it as a "possibility" - although he did recently tell a German newspaper that there should be a referendum next April.
The Socialists want it earlier, preferably in February, when Spain votes.
Even some mainstream politicians say this is a fuss about nothing.
Former Socialist minister Guilherme d'Oliveira Martins, who represented Portugal's parliament at the Convention, the body that framed the European Constitution, has said the date is of "marginal" importance.
So voters are left guessing as to what question they might be asked, and when.