Joe Biden became the first president to ever walk a picket line on Tuesday as he rallied striking autoworkers in Michigan.

Donald Trump has taken a rather different tack with the United Autoworkers strike. Last week, the GOP frontrunner expressed sympathy for the UAW and announced that he would be traveling to the Detroit area to speak to autoworkers. In doing so, he generated myriad headlines about how he was courting striking autoworkers, in a populist departure for a Republican presidential candidate.

Then, his campaign disclosed that Trump will actually be addressing a nonunion auto-parts plant that is effectively undermining the strike.

These two approaches to the UAW’s fight perfectly encapsulate the two parties’ disparate orientations toward labor issues writ large.

Democrats and Republicans both wish to portray themselves as champions of the American worker. To an extent, this has always been true; to win power in a democracy, you need to claim some affinity for the most populous social class. But the competition for America’s populist mantle has intensified in recent years.

For decades, non-college-educated voters have been drifting rightward while university graduates shifted left. Trump’s 2016 campaign accelerated these trends, peeling off a critical mass of working-class Obama voters in pivotal Rust Belt states.

This development, in combination with an ascendant progressive movement, led the Democratic Party to align itself more tightly with organized labor, and loosen its attachment to a meritocratic conception of social justice. Whereas Barack Obama sometimes posited access to higher education as the antidote for inequality, Biden has concentrated both rhetorically and substantively on improving employment prospects for blue-collar laborers. In his first address to Congress, the president advertised that “nearly 90 percent of the infrastructure jobs created” in his economic plan “do not require a college degree; 75 percent don’t require an associate’s degree.” At the same time, the Biden administration has abandoned its Democratic predecessor’s fight with teachers unions over education-reform policy. And it has also curried favor with unions in the manufacturing sector by federally subsidizing domestic production and seeking to re-shore critical industries. More fundamentally, the president’s National Labor Relations Board has taken aggressive steps to abet union organizing.

Meanwhile, at the state level, Democrats have sought to improve working conditions by raising the minimum wage and creating statewide boards empowered to set minimum standards in certain sectors.

The Democrats will never be mistaken for a labor party. Unions are too weak in the U.S. for a party unequivocally committed to workers’ interests to wield national power. This reality was made manifest in the fight over Biden’s proposal to establish a special tax credit for union-made electric vehicles. Although the AFL-CIO fought hard for that provision, Democratic senators in low-union-density states resisted it, as it would have effectively encouraged auto companies to ramp up production in Michigan instead of building new factories in West Virginia, Georgia, or Arizona. Further, myriad business lobbies exert influence within the Democratic tent, as do upper-middle-class voters whose aversion to higher taxes constrains the party’s redistributive ambitions.

Nevertheless, organized labor is the most powerful mass-membership institution within the Democratic coalition. And as competition for working-class voters’ allegiances has intensified, the party has increased its support for organized laborers in their conflicts with management.

The GOP’s bid to claim the title of “workers’ party” has been far more superficial. The party has popularized cultural controversies that cleave highly educated liberals from the median working-class voter, even when those conflicts have few policy implications or material stakes. Trump, for his part, has an eye for publicity stunts that convey an ostensible solidarity with working people, as when he used the bully pulpit to pressure Carrier Global Corp to refrain from relocating production to Mexico, advocacy that failed to avert hundreds of layoffs at that firm once the media spotlight had shifted.

Trump and the GOP can make substantive appeals to blue-collar workers in discrete sectors. Although Republican officialdom has no interest in siding with unions in their conflicts with management, it is perfectly comfortable backing extractive industry in its disputes with environmentalists. And it is plausible that some workers in the fossil-fuel and mining industries have material reasons to favor Republicans over Democrats, although the substantive difference between the two parties on these issues is commonly exaggerated (under Biden, U.S. oil production hit record highs).

When it comes to policymaking that concerns all working people as working people, however, Republicans remain as committed to the interests of bosses as they’ve ever been. Under Trump, the GOP restricted workers’ rights to organize certain categories of workplaces, made it easier for employers to bust unions, denied guaranteed overtime pay to 12.5 million workers, effectively transferring $1.2 billion from their paychecks to their bosses’ bank accounts, proposed a rule allowing companies with fewer than 250 workers to cease reporting workplace injuries and illness statistics to Occupational Safety and Health Administration (OSHA), asked the Supreme Court to uphold the right of employers to include forced arbitration clauses in contracts (thereby denying workers the capacity to press complaints against their bosses in open court), and restored the right of serial labor-law violators to compete for government contracts, among other things.

Biden and Trump’s approaches to the UAW strike illustrate these two distinct orientations in miniature.

Biden initially resisted calls for him to walk the picket line with striking autoworkers. There is no precedent for a president to intervene in a private-sector labor dispute in quite that manner. And the administration needs the cooperation of auto executives in order to meet its goals for the electric-vehicle transition. Nevertheless, with the UAW withholding its 2024 endorsement, Trump threatening to woo the union’s membership, and persistent lobbying from the AFL-CIO, Biden chose to do the unprecedented.

Speaking to workers in Michigan, Biden declared, “Wall Street didn’t build this country, the middle class built this country. The unions built the middle class. That’s a fact. Let’s keep going, you deserve what you’ve earned. And you’ve earned a hell of a lot more than you’re getting paid now.” Asked by a reporter whether he was specifically endorsing the UAW’s demand for a 40 percent pay increase over the life of the next contract, a chorus of chanting workers pressured Biden into saying “yes.”

Trump, by contrast, never actually endorsed the UAW in its fight with the management of the Big Three automakers. Rather, he suggested that the real threat to UAW members’ interests are the environmentalists pushing the “all Electric Car SCAM” (a narrative that weaves a tapestry of lies around a single important half-truth). He then insinuated that he would be addressing striking workers, a gambit that succeeded in generating a week of headlines about the Republican front-runner’s heterodox courting of the union vote:

And yet, as Jacobin’s indispensable labor reporter Alex Press noted, Trump’s rally with striking autoworkers proved to be entirely fictional. In reality, the Republican candidate accepted the invitation of a (seemingly) conservative small business owner to speak to a crowd of nonunion auto-parts manufacturing laborers, whose ongoing work directly reduces the leverage of striking workers in their sector.

The business in question, Drake Enterprises, is a prime venue for a diatribe against electric vehicles; since EV powertrains require far fewer parts than internal combustion engines, the green transition poses a profound threat to parts makers. But holding a rally at a nonunion shop amid a strike is the opposite of demonstrating solidarity with striking unionists.

One party is capable of rallying to labor’s side, when presented with sufficient intra-coalitional pressure and electoral incentive. The other party will project a populist image while channeling workers’ grievances toward targets other than their employers and partnering with low-road businesses to erode labor’s bargaining power. Whatever else comes out of the UAW’s strike, it has at least made the choice facing American workers clear.