The unions have also had very concentrated campaigns in advance of Janus to get members involved. The American Federation of Teachers is having one-on-one meetings with members and potential members, asking them to sign “recommit” cards in 10 states to promise that they’ll continue to be union members. The union currently has 530,000 recommits, a spokesman told me. (It has 1.7 million members.) One Toledo union has 100 percent of its members recommit, Weingarten said. Similarly, the National Education Association, or NEA, is reaching out to members and trying to convince them that a union can help them fight for racial justice and equal distribution of resources, rather than just for salary wages, according to Testerman. Members are motivated to join when they think about how unions will be advocates for teachers and the communities they serve. “When people actually see a movement that is giving voice to their profession and their students, they join their union,” he told me.

Left-leaning states have also tried to prepare for Janus by passing laws that will make it easier for unions to recruit members, even if they can’t collect agency fees. In California, for example, unions now have the right, thanks to a new law, to meet with new public employees as soon as they start working. A second new law keeps private the phone numbers and email addresses of employees of public agencies, so that anti-union groups will have a harder time convincing them to drop out of unions.

Despite these efforts, there will almost definitely be some drop-off after Janus. The NEA is budgeting for a 15 percent decrease in revenues next year, for example. The question is how much unions can successfully delay membership declines. Some of this may also depend on what’s next for the anti-labor movement. In Wisconsin, for instance, once a labor movement stronghold, an initial anti-union foray led to more laws passed that hamstrung labor. First, in 2011, Governor Scott Walker passed Act 10, which dramatically curtailed collective bargaining for most public-sector workers and required that unions be “recertified” every year by a majority of people eligible to vote, counting people who didn’t vote as a “no.” Wisconsin then became a right-to-work state in 2015, preventing unions from collecting fair-share fees from private-sector employees who chose not to join the union. The crippling and nonstop attacks on unions has led to a dramatic decline in unions in Wisconsin—in 2011, 13.3 percent of workers were members of unions; today, just 8.3 percent are. This has also led to a drop in salaries and benefits. Median salaries for teachers in Wisconsin fell 12.6 percent, or $10,843 dollars, between 2012 and 2015.

Yet improbably, even union members in Wisconsin say that the worst days are behind them. As I talked to union representatives, a few referred me to the Milwaukee Teachers’ Education Association, which they said had been successful at surviving the onslaught of anti-union legislation. Success is relative in a place where conservatives are in charge. Before Act 10, MTEA had 7,500 dues-paying members, Amy Mizialko, a vice president at the union, told me. Today, it has about 4,800. But MTEA has been focused on building a better union that is focused not just on wages and benefits, which it isn’t allowed to bargain for, but instead on social justice and issues that are important to teachers. The union has gotten more teachers involved by talking not just about the union benefits teachers, but also how it benefits students.