Albert Hunt: U.S. political stability may depend on wages

Labor Day 2017 might be a cause for celebration. This is the third-longest economic expansion in history — almost 100 months. Unemployment is approaching a 16-year low, and employers are looking to hire.Yet for many working- and middle-class families across America, these good tidings are overshadowed by a sobering reality: Wages and their purchasing power remain flat.This is a long-term trend, decades in the making. More recently, affluent Americans have recovered beautifully from the Gre