Predloženi sporazum o ustavu EU bi bio pomogao u uklanjanju postojećih ograničenja daljnjem proširenju, ali on je stavljen na led nakon što su ga prošle godine na odvojenim referendumima odbili glasači u Holandiji i Francuskoj, čime je izazvana jedna od najgorih kriza u historiji bloka.
A proposed EU constitutional treaty would have helped clear the existing limitations to further enlargement, but it was put on ice after Dutch and French voters rejected it in separate referendums last year, triggering one of the worst crises in the bloc's history.