When Joe Biden announced he would drop out of the 2024 presidential race and endorse Kamala Harris in his stead, unions were muted in their initial response. Harris, formerly a senator from California, isn’t entirely without pro-union credentials: most notably, she introduced the Domestic Workers Bill of Rights in 2019, which would rectify domestic workers’ exclusion from the protections of the National Labor Relations Act (NLRA), a move that solidified her strong support from the Service Employees International Union (SEIU).

But the vice president’s record on labor is far thinner than Biden’s, whose willingness to walk a picket line as a sitting president, combined with his worker-friendly appointments to the National Labor Relations Board (NLRB), distinguished his presidency as pro-worker (though his shortcomings, particularly during railworkers’ dispute over grueling schedules and a lack of sick days, shouldn’t be stricken from the record).

Attempting to shore up critical union support, Harris recently said that she’d pass the PRO Act, the wide-ranging labor-law reform legislation that would empower workers to unionize, which has been stalled in congressional limbo for years. It’s good that the Democratic presidential candidate is setting that expectation (even if most Democratic nominees have made similar such pledges over the last half-century that have amounted to little). But the actual passage of such legislation depends far more on the makeup of Congress; given Republican representatives’ near-unanimous refusal to support the measure, it’s likely to go nowhere.