French President Nicolas Sarkozy's visit to Poland on Thursday could tip the balance in persuading its eurosceptic conservative leaders not to veto talks on a new European Union treaty.
Twin Polish leaders, President Lech and Prime Minister Jaroslaw Kaczynski, have threatened to block the treaty to reform EU institutions unless European leaders also agree to discuss a proposal that would give Warsaw more voting rights.
Most commentators agree the centre-right French leader, seen by the Kaczynskis as one of their closest allies, has a better chance than anyone of getting them to drop the veto and avoiding deadlock at an EU summit next week.
"If Sarkozy doesn't manage to sweet talk the Kaczynskis, it is highly unlikely that anyone else will soften them up," said Pawel Swieboda, an analyst at DemosEuropa, a Warsaw based European think tank.
"The Kaczynskis admire him and even if they don't drop the veto plans after his visit, there is a chance that they will change their drastic language and that gives hope." Spanish Prime Minister Jose Louis Zapatero will come to Poland to discuss the treaty on Friday and Germany's Chancellor Angela Merkel will talk to the Polish president on Saturday, but they are seen as having less influence over the Kaczynskis.
"I will try to convince the Polish leaders that Poland became such an important country that we need its agreement on the compromise in the form of a simplified treaty," Sarkozy told Polish daily Gazeta Wyborcza on Wednesday. Sarkozy, who took office last month, has said an agreement on the EU treaty at the Brussels summit is a political priority.
The Kaczynskis won elections in 2005 promising to take a tougher stance towards the European Union only the year after it joined. Since then, relations with Brussels have been soured by verbal skirmishes and disputes about power sharing.