Treaty of Nice

The Treaty of Nice reformed the institutional structure of the European Union so that it could withstand eastward expansion, a task that the Amsterdam Treaty had been meant to accomplish but had failed to address. European leaders signed it on 26 February 2001, and it came into force on 1 February 2003. It amended the Maastricht Treaty, also known as the Treaty on European Union, and the Treaty of Rome, which established the European Community and, before the Maastricht Treaty, the European Economic Community. Its entry into force was in doubt for a time, because Irish voters rejected it in a referendum in June 2001, a result that was reversed in a second referendum held a little over a year later.