The shrinking middle class and growing income inequality within the United States aren't products of bad trade deals. The situation is more complicated than that and involves technology, tax policy, education and changing demographics. And while the loss of high-paying blue collar jobs is clearly a factor, the answer isn't to build a proverbial fence around livelihoods destined to go the way of buggy whip making — it's to increase U.S. competitiveness and productivity. Steelmaking and coal mining might have been big job producers a century ago, but it's far better for the U.S. to focus on technology, aerospace, advanced materials, medical technology, pollution controls, computer software, biotechnology and other sectors with high-growth potential. Under Armour may be working to bring manufacturing to Baltimore, but it's not talking about rooms full of low-skill workers with sewing machines. It's opening a facility with robots, 3D printers and workers in lab coats.