A vote in Poland’s parliament today (18 March) could force Prime Minister Donald Tusk to subject the EU’s new 'Lisbon Treaty' to a public referendum, after the opposition party threatened to reject a bill allowing for its ratification.

Former Prime Minister Jaroslaw Kaczynski, who leads the opposition since snap elections last October, insists he will only approve the bill if legal guarantees are included to ensure the country’s sovereignty on major decisions. Another key demand refers to an opt-out from the Charter of Fundamental Rights, which, as Prime Minister, he had obtained, after intense lobbying, in exchange for Poland’s approval to the new Treaty (EurActiv 19/10/2007).

Kaczynski’s Law and Justice Party (PiS) fears the Charter would limit Warsaw’s ability to maintain its traditional Roman Catholic family policy, which only recognises marriages between a man and a woman. President Lech Kaczynski – who has the power to veto the Treaty's adoption – has backed the PiS position, saying he would not approve any bill legalising gay marriage - and he fears the Charter does exactly this.

The President is also concerned that the Charter could open the door to Germans reclaiming individual ownership rights on land granted to Poland after World War II. "There are […] certain threats to our national interests" in the Treaty, he said, although he did not specify in what way the Charter might affect territorial issues.

While he insisted that he had no "intention to quarrel" and that he was open to compromise as long as it was "the best solution for Poland", President Kaczynski said, on 17 March, that he may propose an alternative ratification bill, which better protects Poland's interests. "I cannot agree to a voluntary and unjustified degradation of our country's position in the European Union," he explained.

The government needs at least seven votes from opposition to secure the two-thirds majority required to pass its own ratification bill. But Tusk has signalled that he might call for a referendum if Parliament proves incapable of ratifying the Treaty.

If this happens, Poland would be one of just two EU members to hold a referendum - the other being Ireland. In the UK, despite heated debates, the House of Commons rejected this possibility earlier this month (EurActiv 06/03/2008).

Nevertheless, in Poland's case, even with a referendum, ratification seems almost certain, with latest polls showing more than 75% of citizens to be in favour of the Treaty.