When it comes to politics, America’s labor unions have a popular maxim: Don’t let political parties take you for granted. What is unspoken there is the subtext: Don’t let Democrats take you for granted. If unions automatically back the Democratic Party—which is much more pro-labor than the Republican Party—then Democratic lawmakers may not feel any need to pursue policies those unions want.

But the Teamsters’ much-publicized decision not to endorse Kamala Harris this week turned that political maxim on its head. The 1.3 millon–member Teamsters union failed to endorse anyone. “Unfortunately, neither major candidate was able to make serious commitments to our union to ensure the interests of working people are always put before Big Business,” Teamster’s president Sean O’Brien said in a statement.

This is plainly shocking and a lose-lose for one of the most powerful unions in the country. As the only union out of the nation’s 10 largest unions not to endorse Harris, the Teamsters made the mistake of taking the Democrats for granted.

Let’s look at the alternative: Donald Trump is an unarguably anti-union candidate. He once said he’d sign a national right-to-work law, he’s denounced prominent labor leaders like UAW president Shawn Fain, and he’s embraced extremely anti-union business leaders including Elon Musk. Trump recently launched a missile at organized labor’s heart by praising the idea of firing striking workers (even though that is illegal under federal law). Three days after O’Brien—in an unusual step for a union leader—spoke at the Republican National Convention to urge the GOP to be nicer to labor, Trump kicked unions in the teeth in his acceptance speech by mocking the United Auto Workers.

Meanwhile, Harris is part of the administration that moved political heaven and earth to enact the Teamsters’ No. 1 legislative priority: an $86 billion bill, passed in 2021, that rescues the underfunded pensions of over 400,000 Teamster members and 2 million union members in all. (Trump opposed that legislation.) Many Democratic politicians must be asking: Why even bother pursuing policies that the Teamsters want if the Teamsters seem to be taking the Democrats and their pro-labor efforts for granted and telling the party to shove it?

In the Teamsters’ news release announcing its nonendorsement, the union defended its decision by citing an internal survey that had found rank-and-file Teamsters strongly favored Trump over Harris. It’s certainly understandable why a union’s president and board would hesitate to endorse a candidate when a majority of members apparently support someone else. I say “apparently” because some Teamster officials ridiculed that internal poll as unscientific and untrustworthy, saying it was based on a survey printed on the back of the union’s magazine, which meant haphazard responses. Moreover, O’Brien’s decision to speak at the GOP convention this year undoubtedly helped push some-to-many rank-and-file Teamsters to back Trump because his appearance there seemed like an embrace of Trump.

But to my mind, that internal survey showing so many Teamsters backing Trump highlighted something else: The union’s leadership must have done a dreadful job informing and educating rank-and-file members about how hugely anti-union Trump is and how aggressively anti-union and anti-worker Trump’s first administration was (and appointees were). Also, Teamster leaders evidently also failed to explain to rank-and-file members that Harris has fought for policy after policy strongly backed by the Teamsters and other unions, including the Protecting the Right to Organize Act, which is the labor movement’s No. 1 legislative priority and would make it considerably easier for the Teamsters and other unions to organize. Trump opposes the PRO Act. Harris also supported the Bipartisan Infrastructure Act, the CHIPS Act, and the Inflation Reduction Act, which together will create hundreds of thousands of good-paying union jobs for Teamsters and other union members. Harris, unlike Trump, also supports increasing the pathetically low $7.25-an-hour federal minimum wage to at least $15.

It should mean a lot to Teamsters and their leaders that Harris has been part of the most pro-union presidential administration in modern history. Not just President Joe Biden, but Vice President Kamala Harris walked on a union picket line. Both Biden and Harris have often spoken out in favor of workers during unionization drives and strikes. While Trump appointed a stream of anti-union, pro-business right-wingers to the federal courts and National Labor Relations Board, the Biden-Harris administration has made one pro-labor appointment after another to the courts and NLRB. Harris was also co-chair of the first White House Task Force on Working Organizing and Empowerment, which issued a report that labor unions enthusiastically applauded. It recommended that the federal government and Congress do many additional things to help workers unionize and strengthen workers’ voices.

This was not lost on the nine other largest unions plus the AFL-CIO, which all endorsed Harris. Together, they have many times more members and a much bigger and more sophisticated political operation than the Teamsters. Many rank-and-file Teamsters see and applaud Harris’ pro-labor record and bona fides. That’s why more and more Teamster locals and regional councils have bucked O’Brien and endorsed Harris, including the statewide Teamster councils in Michigan and Wisconsin, and the western Pennsylvania council. They strongly disagreed with O’Brien’s claim that Harris has failed to make “serious commitments” to “ensure the interests of working people.”

A major reason the Teamsters gave for not backing Harris or Trump was that neither would commit not to interfere to prevent a threatened strike, such as a coast-to-coast rail walkout. Many Teamsters remain angry at Biden for signing legislation in December 2022 that blocked a threatened nationwide rail strike. The Teamsters board seemed to be making this a litmus test, wanting Harris and Trump to pledge not to block a national rail strike even though presidents and Congress are specifically empowered to do so under the Railway Labor Act.

It’s unfortunate that the Teamsters’ leadership isn’t more understanding of a president’s difficult position. Let’s recognize reality—if a president and Congress fail to invoke their powers to avert a rail strike, that could prove economically and politically disastrous. Such a strike could last for weeks and pummel the nation’s economy, hurt millions of workers across the U.S., and drag down a president politically. Trump, who openly supports firing strikers, could never be expected to agree not to prevent a rail strike, but the Teamsters seemed to be demanding that Harris agree to walk the plank on this issue. She would look weak and be widely condemned and mocked if she bent the knee to the Teamsters on this, pledging never to block a potentially calamitous rail strike.

When Sean O’Brien ran to be president of the mighty Teamsters union, he promised to be a strong leader. But in the Teamsters’ messy handling of a presidential endorsement, O’Brien has appeared weak, short-sighted, and feckless. He has failed to provide strong leadership on one of his most important tests: to get his union’s rank-and-file and board to reject anti-union Trump and instead embrace Harris, who has year after year been a champion of America’s unions and workers. The Teamsters’ nonendorsement is widely seen as a blow to Harris, and that nonendorsement, together with O’Brien’s appearance at the Republican convention, could definitely help deliver victory to Trump in November—something that O’Brien and his union will end up regretting because a second Trump administration will probably be even more of a danger to unions (and democracy) than the first one.