Teachers’ fortunes are emblematic of public workers’ more generally since the Great Recession. Because of the stable nature of government employment, such employees were largely spared the worst of the layoffs and wage cuts that afflicted private businesses. That said, these jobs have not rebounded in the same way that many private-sector ones have, either, with public finances still squeezed, public workforces still smaller than their pre-recession peak, and local government officials still hesitant to make critical investments in their workforces and infrastructure.

Granted, by many measures and in many places, teaching remains a solidly middle-class profession. Government data shows that the average teacher earns about $59,000 a year, with many school districts offering good benefits and generous retirement plans. Andrew Biggs, an economist at the conservative American Enterprise Institute, pushed against the notion that teachers are broadly underpaid. “It’s a good and a very family-friendly job,” he told me, citing its reasonable hours and long summer break. “Why should you pay them more? They’re on strike—that’s a reason to pay them more.”

Yet in some states, teachers are earning close to poverty wages, as the West Virginia strike and the threatened Oklahoma strike have demonstrated. Indeed, those two states offer compensation roughly a third lower than the national average for all public teachers, numbers that do not look much better adjusting for the cost of living. Moreover, there is data demonstrating that the teacher pay gap—meaning what public-school teachers earn compared with comparably qualified individuals in the private sector—is large and growing. The left-of-center Economic Policy Institute (EPI) has found that teachers’ average weekly wages actually fell $30 per week between 1996 and 2015 after adjusting for inflation, whereas they increased measurably among all college graduates. EPI also has estimated that public-school teachers were earning about 2 percent less than comparably qualified private-sector workers in 1994, a disparity measure that grew to 17 percent by 2015.

“Teachers actually gained ground in the depths of the recession, as their pay didn’t fall, whereas pay for other workers did,” Larry Mishel, an economist at EPI, told me. “But when there was a recovery, they didn’t get much recovery.” Indeed, as state and local finances rebounded, many red and purple states cut their income taxes, with property taxes remaining depressed due to the subprime-mortgage crisis. The result: sharp declines in public-school funding per student, reduced salary increases through the recovery, and widespread teacher shortages. Teacher enrollments dropped from 691,000 in 2009 to just 451,000 a year in 2014 as attrition—meaning the share of educators dropping out of the profession—hit 8 percent a year.* Nationwide, the number of teachers and other school workers has fallen by 135,000 since 2008, a recent analysis of government data by the Center for Budget and Policy Priorities, a left-of-center think tank, found. Yet as that number declined, the number of students rose by 1.4 million.