Harris and Walz, in Crucial ‘Blue Wall’ States, Rally for Union Support

Vice President Kamala Harris, seeking to press her advantage with union voters, stormed into Detroit for a Labor Day union rally on Monday, telling organized-labor supporters that the country celebrates unions “because unions helped build America.”

Ms. Harris and her running mate, Gov. Tim Walz of Minnesota, were barnstorming through the so-called blue wall states of Michigan, Pennsylvania and Wisconsin on Labor Day, appealing to union voters as the ground troops of a campaign that has barely two months left. Ms. Harris was to appear in Pittsburgh on Monday evening with the man she seeks to succeed, President Biden. There, she planned to back Mr. Biden’s opposition to the proposed takeover of U.S. Steel by Nippon Steel of Japan.

At Northwestern High School in Detroit, the vice president was greeted onstage by the presidents of unions representing autoworkers, laborers, utility workers and teachers.

“I tell people, you may not be a union member, but you better thank a union member,” she said, attributing union action for paid leave, vacation time, higher wages and safer work conditions.

The question hanging over the day, however, was just how important unions remain in an American labor force where they represent just 1 in 10 workers, half the percentage they once represented in the 1980s. It is also not clear whether union members, especially in the old-line industrial and laborer unions, will side with the Democratic ticket as overwhelmingly as they once did, as Donald J. Trump continues his courtship of the working class.

In Detroit, Michigan’s Democratic luminaries — Gov. Gretchen Whitmer and Senator Debbie Stabenow, and hopefuls like Representative Elissa Slotkin, who is running for Ms. Stabenow’s Senate seat — shared the stage with Shawn Fain, president of the United Automobile Workers; Brent Booker, general president of the Laborers’ International Union of North America; and Randi Weingarten, president of the American Federation of Teachers, among others.

In contrast, Mr. Trump appeared at least publicly to take the day off. He and the chairman of the Republican National Committee, Michael Whatley, released statements praising American workers without once mentioning unions.

“We were an Economic Powerhouse, all because of the American Worker!” Mr. Trump wrote in a statement and on social media. “But Kamala and Biden have undone all of that.”

Mr. Whatley wrote, “Today we celebrate the vast contribution of American workers.”

Mr. Biden won over union voters by 22 percentage points in 2020, according to a Harvard University study, considerably better than Hillary Clinton had done in 2016, when she narrowly lost the presidential election. But even Mr. Biden’s performance was an erosion from when Bill Clinton won union voters by 31 points in 1992.

Union leaders have promised on-the-ground muscle to get out the vote for Ms. Harris, rally their members and pull in groups that have slid toward Mr. Trump, especially white, male workers in and out of organized labor. Working America, a community organizing arm of the A.F.L.-C.I.O., has been heading outreach to nonunion families.

“The truth of the matter is, there are tens of millions in critical battleground states who are not only reachable but movable,” said Matt Morrison, Working America’s executive director.

But even union officials were not all that certain their ground efforts were breaking through. Terrell Garner, a training instructor for the laborers union’s 5,000-strong local in Detroit, spoke at length of the education efforts the union is making with members and their families and friends, the phone banking and door knocking on weekends in pivotal Michigan.

But when asked how it’s looking for Ms. Harris, he held out a hand and rocked it back and forth: “Eh, 50-50,” he said with a sigh.

“As they become more educated, they do find themselves on our side of the fence,” he added, but time is running short for that effort. Mail-in voting in Michigan begins in just over three weeks.

Union leaders were far more positive. Michigan could hold the key to the White House, but also control of the Senate and the House, with two open House seats, a highly competitive Senate race and a neck-and-neck contest between Mr. Trump and Ms. Harris. In an interview, Ms. Weingarten said her union’s footprint in Michigan was growing as the A.F.T. unionizes higher-education employees, health care workers, librarians and even some doctors.

“What we’ve learned is that people really trust teachers and nurses,” she said. “It’s part of the reason why the extremists are trying to disconnect that relationship,” especially after the Covid pandemic, she added, as conservatives have pitted the teachers’ union against health care workers.

But Mr. Trump’s appeal to working-class voters is undeniable. The one union leader not aboard Ms. Harris’s campaign, Sean O’Brien, president of the Teamsters, has continued his dalliance with the former president, resisting pressure from the main Black teamsters organization and some large locals that have shattered precedent by endorsing Ms. Harris on their own.

Appearing on CBS’s “Face the Nation” on Sunday, Mr. O’Brien continued to move the goal posts on an endorsement. He had once said it would come after both parties held their conventions. Now he said the Teamsters cannot endorse until their leadership sits down for an interview with the vice president.

“We represent 1.3 million members,” he said. “Half of our members are Republicans, half of our members are Democrats. So we have to serve all of our membership equally.”

In fact, Teamsters officials say that in a straw poll of locals before President Biden left the race, a plurality of Teamsters members voted for Mr. Biden over Mr. Trump, but Mr. O’Brien has not released the results of that straw poll. Last month, he met with Mr. Trump at his seaside mansion in Palm Beach, Fla.

Representative Haley Stevens, a Michigan Democrat, said on Monday there was still work to do in educating union members and their families about concrete steps Mr. Biden’s administration has taken to favor union workers. But she said new union leaders like Mr. Fain were taking steps beyond traditional organizing, showing up at workplaces, reaching beyond union members and targeting white working-class men.

The pitch is granular, she said, describing it as, “We are reauthorizing an infrastructure bill next year. Who do you want in the White House?”

“We can’t say it from the top,” she added. “We have to go into the neighborhoods.”