Last week, both President Joe Biden and Donald Trump traveled to Michigan. Many in the media cast these visits as similar efforts to woo union voters for the 2024 election. But that is mostly wrong or misleading.

The visits were clearly not symmetric pro-union efforts. Biden walked a picket line in support of the United Auto Workers (UAW)—something no other president in history has done—and told them: “Folks, stick with it, because you deserve the significant raise you need.” Trump, on the other hand, accepted an invitation from the management of a non-union auto parts firm to appear at its factory. He then downplayed the UAW strike, telling his audience that the current negotiations “don’t mean as much as you think” while mostly ranting against electric vehicles.

The impact on next year’s election remains to be seen. But if working people vote based on who truly has their interests at heart—rather than who has repeatedly chosen to put corporate interests above those of workers—that will greatly favor Biden. If, instead, both candidates are portrayed as earnestly courting working-class voters, then the waters will be muddier.

But to assess the two visits to Michigan mainly in terms of their potential effect on the 2024 election is to think too small. The single most important trend in U.S. economic life in recent decades has been the rise of income inequality, which was overwhelmingly driven by anemic growth in wages for all but the very highest-paid workers.

In turn, perhaps the single largest driver of this rise in inequality has been the undermining of the power of organized labor and the subsequent decline of unionization and collective bargaining. If Biden’s walk on the picket line is one signal of a resuscitation of labor’s power, this could lead to a better economic life for low- and middle-income families for generations to come.

The mid-20th century spread of unionization is what built the middle class in America. Two factors drove it: a huge amount of grassroots organizing, and a concerted policy push under Franklin Roosevelt’s New Deal that supported unionization.

One plank was the National Labor Relations Act of 1935 (the Wagner Act), which encouraged collective bargaining by protecting workers’ full freedom of association. Another was the attaching of strong pro-labor conditions, and conditions that fought against racial discrimination by employers, to the massive federal defense spending up to and during World War II.

Each of these policy efforts was controversial at the time, yet they were the foundation of a union-built middle class in the U.S. And each has clear analogues in today’s policy debate, where efforts to fundamentally reform labor law and to attach pro-labor conditions to large new tranches of federal investment are also under way.

The grassroots organizing that flourished in the mid-20th century is once again in place today. The energy and support for unionization are at levels not seen in decades. Workers are filing petitions for union elections and against unfair labor practices at rates not seen since the 1950s. In recent months, tens of thousands of workers, from Hollywood writers, delivery workers, and baristas to hotel workers, nurses, and auto workers, have gone on strike or threatened to do so.

But unlike in the mid-20th century, today’s labor law is a massive impediment to increased unionization. Labor law is now so weak that union-busting is simply a cost of doing business for most companies, and not a very large cost at that.

The obstacles that workers face in unionizing and securing a first contract are colossal. The National Labor Relations Board has a great deal to carve out better protections for workers’ right to organize—but their efforts need a serious legislative boost if they are to fundamentally rebalance the playing field.

At the federal level, this would require the Protecting the Right to Organize (PRO) Act, and its public-sector counterpart—the Public Service Freedom to Negotiate Act. These would be the first federal pro-labor legislative reforms since the Wagner Act, rebuilding the right of workers to unionize and bargain collectively, but with modernizations that address many of the ways that employers in recent decades have short-circuited organizing efforts. These would need to be accompanied at the state level by the overturning of so-called right-to-work laws and the passing of legislation that supports collective bargaining for public-sector workers.

Further, the labor standards attached to many of the investment projects launched under the Biden administration must be implemented assertively and, where possible, expanded. The link between industrial policy and labor standards has a rich, successful history in this country, as seen during Roosevelt’s administration before and during World War II. That should be continued now.

Such measures will help to ensure that the organizing push we are currently experiencing leads to lasting change. Any candidate not focusing on policy efforts to secure workers’ fundamental right to organize has no serious claim to care about the U.S. working class. And random trips to non-union plants in Michigan don’t change that.