(AP Photo/Adam Beam) Su Sheridan holds a sign protesting proposed cuts to retirement benefits for public school teachers on March 8, 2018 in Frankfort, Kentucky. trickle-downers_35.jpg A round seven years ago, I had a standard wisecrack to explain the standing of workers in the world’s two dominant economies: “China has strikes but no unions; America has unions but no strikes.” Seven years later, it’s clear we’re becoming more like China every day. The remarkable upsurge of teachers in Republic-run, largely non-union states that has swept through West Virginia and is now sweeping through Oklahoma and Kentucky, and is poised to descend on Arizona, has returned the mass strike to the United States after decades of relegation to the history books. In each of these states, the teachers unions have something between limited and no legal rights to bargain collectively, and, correspondingly, represent just a hard core of members whose commitment to their union is more a matter of belief than...