Today (or Friday, May 1 itself) is a bank holiday in most of Europe to celebrate May Day, a slightly more explicitly socialist version of America’s Labor Day. And it happens with unions increasingly involved in strategic business decisions around the world: the UAW is soon going to control Chrysler and have a very large stake in GM; the German autoworkers effectively have a veto over whether Fiat’s Sergio Marchionne can fulfill his ambition of creating an intercontinental automaker spanning Italy, Germany, the US, and Latin America; and the outcome of tense negotiations with its biggest union will determine whether or not Boston still has its own daily newspaper come next week.