By Gabriel Partos
BBC South-East Europe analyst
Hungarians are voting on Sunday in a highly controversial referendum to decide whether parliament should draft a law on giving Hungarian citizenship to ethnic Magyars living outside Hungary's borders.
The governing Socialist-liberal coalition is opposed to it, on the grounds that it might encourage large numbers of Magyars from less prosperous neighbouring countries to settle in Hungary. That would add a huge burden in terms of welfare, health and education costs.
Hungary's ruling Socialist-liberal coalition is against the Magyar plan
According to opinion polls, the majority of Hungarians support the initiative. But it is by no means certain that a sufficient number will turn up to make the vote valid.
And even a vote in favour of granting citizenship would leave it to parliament to work out the details of the actual legislation.
Although the outcome of the referendum is surrounded by uncertainty, it has already led to a dispute between Hungary and neighbouring Romania.
Romanian Prime Minister Adrian Nastase, who is facing a second round of voting in his country's presidential race on 12 December, has denounced the Hungarian initiative as "insane", and has criticised several of its provisions.
"The idea that citizenship can be granted to compact ethnic groups, the way one spreads chemical fertilisers over a field, is totally incompatible with the provisions of constitutional law," he said.
Nastase needs broad support in the second round of elections
"Citizenship is granted to individuals."
Mr Nastase is in a difficult position. Although he is ahead of his centrist rival, Traian Basescu, after the first round of the presidential contest, he needs to get support from two very different political camps to ensure his victory.
Romania's ethnic Hungarians, united behind their party, the Democratic Unions of Hungarians in Romania, gained 6% of the vote in Sunday's parliamentary elections.
Their party has already declared that it will give its backing - as it has done over the past four years - to Mr Nastase's Social Democrats in their effort to form a new government.
But the other political factor, the ultra-nationalist and strongly anti-Hungarian Greater Romania Party, gained twice as many votes as the ethnic Hungarians.
Greater Romania is beyond the pale as far as possible coalitions are concerned because of firm opposition to it from the European Union. But a substantial section of its supporters is needed for Mr Nastase's election.
That may explain why he has turned up the volume of his rhetoric. And he is not alone. His Foreign Minister, Mircea Geoana, who is expected to take over as prime minister at the head of an incoming Social Democrat-led government, has implied that there would be problems for Romania's ethnic Magyars if they accept Hungarian citizenship.
His comments, in turn, have been criticised by a senior ethnic Hungarian politician, Senator Gyoergy Frunda.
"Mr Geoana knows very well, I think, that the Romanian Constitution allows dual citizenship. And, according to [recently] adopted changes, it grants access to public offices to people who hold dual citizenship."
But for now, Romania's ethnic Hungarians are trying, on the whole, to keep out of the row.
They are in a strong position because whoever forms the next government in Bucharest will need their support - if Romania is to have a viable government and be able to join the EU, on schedule, in 2007.
In the meantime, they are hoping that the referendum in Hungary will succeed; and that the Romanian government will come to terms with that. But it is unlikely that this Sunday's referendum will put an end to the various arguments.
If it succeeds, parliament may water down its broad provisions. If it fails, the whole subject of Hungarian citizenship may be revived in future if a more nationalist government is elected.