A week from today, Europeans may be able to gauge how high the tide of populism and nationalism has risen within their countries and on their continent. For all the returns will be in from three days of elections in the 28 nations represented in the European Parliament. Expectation: Nationalists and populists will turn in their strongest performance since the EU was established, and their parliamentary group -- Europe of Nations and Freedom -- could sweep a fourth of the seats in Strasbourg.