The future of the EU is at stake as Europe's leaders face a new fear: Voters
If elected, Le Pen has vowed to hold a referendum on French membership in the E.U. And if France pulls out, many pro-European advocates believe the entire project would fall apart. “If Marine Le Pen wins, that will comprise an existential shock to the E.U. and for stability in Europe,” said Simon Tilford, the deputy director of the London-based Centre for European Reform.