A (New) Lost Generation: As the media focus on a slight drop in unemployment, an ugly trend gets ignored: the declining participation of young Americans in the job market. We'll pay for this for decades to come. We keep hearing the job market is "improving" or even "solid," with 162,000 new positions created in July and unemployment falling to 7.4%, the lowest since 2008. But one group is sitting it out. And it's the one that most enthusiastically embraced Barack Obama in both of his presidential elections: America's young. Their unemployment rate is a shocking 16.1%. Increasingly, those ages 18...