BRUSSELS – The European Commission president had no reason to expect anything but another bad day. Then, out of the blue, after three years of back-biting and seemingly daily financial crisis, the European Union won the Nobel Peace Prize for fostering peace on a continent long ravaged by war.

It was a badly needed morale boost for a 60-year-old union in the midst of a midlife crisis.

Even as it announced the award Friday, the Norwegian prize jury warned that the financial crisis challenging the 27-nation bloc's unity could lead to a return to "extremism and nationalism." It urged Europeans to remember the EU's role in building peace and reconciliation among enemies who fought Europe's bloodiest wars, even as they tackle the economic crisis that threatens its future.