Now we know the date for Britain's referendum on leaving the European Union, it is June 23. See a RealClearWorld story about the vote. This vote may be the most consequential event Europe experiences this decade.
If Britain votes to leave the EU, certainly other nations will take a long second look at their membership. At least some of those will exit too.
Those nations choosing to remain may eventually achieve political integration, overcoming great obstacles. Given Europe's history, forming a continent-wide "United States of Europe" was probably always a forlorn hope doomed to failure.