The International Brotherhood of Teamsters may be sealing Vice President Harris’s fate by declining to endorse a presidential candidate. If President Trump prevails, expect Democrats to lament persuading President Biden not to run — déjà vu from 2016 when they convinced him to step aside for Secretary Clinton, who proved the weaker candidate.

In the Electronic Member Poll of Teamsters, Trump won in a landslide with 59.6 percent to Ms. Harris’s 34 percent. In a phone poll, he prevailed 58 percent to 31 percent. It’s a huge drop of support from Mr. Biden. Members chose him over his predecessor by eight points, 44.3 to 36.3 percent, prior to Democrats swapping candidates. 

“After reviewing six months of nationwide member polling and wrapping up nearly a year of rank-and-file roundtable interviews with all major candidates for the presidency,” the general executive board for the Teamsters wrote in a statement yesterday that they had “few commitments on top Teamsters issues from either” Trump or Ms. Harris. 

In every election since 1960 except 1976 and 1996, the Teamsters have anointed a candidate, with President George H.W. Bush being the last Republican to win their favor in 1988. This year, the executive board said they “found no definitive support among members for either party’s nominee,” ignoring the results of their own poll.

“If you choose not to decide,” the band Rush sings in “Freewill,” their 1980 hit, “you still have made a choice,” and abstaining from an endorsement has implications almost as large as backing Trump. The BBC called the non-endorsement “a major blow to the Harris campaign’s efforts to win over working-class voters.” 

With over 1.3 million members nationwide — including thousands in key states like Michigan, Pennsylvania, and Wisconsin — Teamsters can tip the scales, especially in close races like 2020. After that election, NPR’s senior political editor/correspondent, Domenico Montanaro, reported that “just 44,000 votes in Georgia, Arizona, and Wisconsin separated Biden and Trump from a tie in the Electoral College.” 

Under the Constitution, the House of Representatives chooses the president in the event of a deadlock, giving each state’s delegation a single vote. In 2020, as now, Republicans hold more states, meaning that Trump would be finishing his second term had he tied Mr. Biden and that he’d prevail if he and Ms. Harris each win 269 Electoral Votes. 

Yesterday, the general president of the Teamsters, Sean O’Brien, wrote on X that for “the past year,” they had “pledged to conduct the most inclusive, democratic, and transparent presidential endorsement process in the history of our 121-year-old organization” to pick a candidate worthy of their power as potential kingmakers. 

Mr. O’Brien professed an open mind in his speech at the Republican National Convention, saying the union was “not beholden to anyone or any party.” That he was not invited to address the Democratic National Convention raised the prospect of a titanic shift rightward.

As Democrats gathered at Chicago without him, Mr. O’Brien told Fox News that there were “big donor classes” at that convention as there had been at the Republican one. “Maybe they didn’t want me to speak there because I would’ve talked to that same group,” he said. “I would’ve exposed those same corporate elitists who attack us every single day.” 

With Trump crushing Ms. Harris almost two-to-one, members made their preference clear. Endorsing the former president would be “what democracy looks like,” just as coronating Mr. Biden would have been had he not withdrawn. Instead, the Teamsters declared all their efforts moot and declined to endorse anyone. 

The BBC also reported that “some Teamsters regional councils representing more than half a million members in Michigan, Wisconsin, Nevada, and California, said they would be endorsing Harris.” That will help soothe the sting she feels, but it won’t wash away the bitter taste in the mouths of members who saw their voices ignored. 

The Teamsters chose not to decide whom they prefer for president, and they still have made a choice. If Ms. Harris loses, there’ll be plenty of casting around for scapegoats. Expect the Teamsters’ to be among them, and for Democrats to wonder if ousting Mr. Biden was the right move or if it cost them union votes in states that could have prevented a second Trump term.