The Dutch official unemployment rate of 4% is the lowest in the E.U. But jobless people over the age of 57½ are not counted as unemployed; neither are almost 1 mil. on disability benefits.

Since the age of steam, the European labor movement has mustered red flags and brass bands on May Day for a traditional show of strength. But this year, post-May Day, Europe faces a labor paradox that Karl Marx never foresaw. While 15 million people are registered as unemployed in the…