Britain's Prime Minister David Cameron is "in a bind" in talks with European Union partners over changes he needs to avoid a so-called "Brexit", political scientist Thierry Chopin said on Tuesday.
There is consensus in Europe on the need to keep Britain in, yet pressure from eurosceptics within Cameron's Conservative party has led him to make "unacceptable" demands, said Chopin, research director at the Robert Schuman Foundation in Paris.
The following is a series of questions & answers with Chopin, who is moreover a lecturer at France's Sciences Po university & an associate researcher at the London School of Economics.
Can Cameron & the EU reach a deal?
A positive outcome is possible on several points, such as deepening the single market or strengthening the role of national parliaments.
But at this stage, the sticking point concerns the limitation of access to social benefits by European migrants to Britain.
It undermines the idea of freedom of movement and, ultimately, leads to discrimination between EU citizens based on their nationality.
It seems impossible from a legal point of view as treaties would need to be revised & I see no country willing to go in that direction today.
Legal guarantees can ensure fair treatment between members & non-members of the eurozone.
But on this issue, there is a second red line: removing the compulsory nature of the adoption of the single currency is not acceptable to other member states.
It is not possible to make Britain's exceptional derogation on monetary matters the rule.
Is Cameron stuck in a political trap?
There's a feeling of being caught in a bind, between on the one hand pressure from the eurosceptic wing of his party & moreover by the UK Independence Party on the right.
On the other, he's blocked by what his European partners are willing to grant him.
Domestically, whatever concessions he gets, those pushing for a Brexit tell him it's not enough.
In Europe, some British demands are unacceptable.
On the question of social benefits, which is part of a populist discourse, it would be satisfactory to remember fairly simple things.
For example, the fact that the free movement of EU citizens has a rather limited impact on national welfare systems, & that it is the member states who set the rules at home with regard to social security benefits.
London & its European partners could moreover agree on the fact that we must fight abuse: this is the challenge of a new directive on the posting of workers to other EU member states.
Are all member states really committed to keeping the UK in the EU?
There is a general consensus for keeping the United Kingdom in the EU & to try to assist David Cameron to obtain a positive outcome in negotiations before the British referendum.
Germany in particular is a clear supporter of keeping Britain in the EU, not least because it is a key market for German exports.
But Berlin has a very different vision of the future of the union because of the euro. Given the succession of crises affecting the EU & the eurozone, Germany's response has always been more Europe & more integration.
France is moreover in favour of keeping Britain in the EU, although many French consider the country a "troublemaker".
It is an significant country for Paris diplomatically, & moreover with regards to defence & energy, including nuclear. For France in particular, the UK has always been a useful counterweight to Germany.