A NEW generation is on the move in Europe, migrating from the fringes of the continent in search of work. The Polish plumber ventured out when his country joined the European Union in 2004, followed a few years later by the Romanian fruit-picker. Now it is the Irish graduate, the Spanish engineer and the Italian architect who are packing their bags. For the people of eastern Europe, migration is a way of catching up with western incomes; for those from the crisis-hit southern and Celtic periphery, it is a means of escaping mass unemployment.This is the way the EU was meant to operate. Goods can move to the consumers; workers can move to the jobs. Migration can relieve the public finances of countries in a slump and fill labor shortages in booming economies. Even so, Europeans remain less mobile than Americans. At their summits, European leaders call for greater mobility to ease youth unemployment and boost growth.But do they really mean it? Migration inevitably causes resentment among some, especially the low-paid. But it has become a more acute political issue with the rise of anti-immigrant and anti-EU parties of all stripes. Increasingly, suspicion that was…