Her appearance in the battleground state of Michigan comes the day after U.S. dockworkers suspended their strike in hopes of reaching a new contract, sparing the country a damaging episode of labor unrest that could have rattled the economy. A tentative agreement was reached to raise salaries, although other issues still need to be resolved.

Harris issued a statement saying the development "indicates progress toward a strong contract and represents the power of collective bargaining." She added that "dockworkers deserve a fair share for their hard work getting essential goods out to communities across America."

Unions have long been a bedrock of support for Democrats, but Harris has failed to secure some key endorsements. The International Association of Fire Fighters announced this week that it wouldn't back a candidate this year, following a similar announcement from the Teamsters. Both unions endorsed Joe Biden four years ago.

It's not a total cold shoulder for Harris. Some Teamsters locals are supporting her, and she won quick endorsements from national teachers unions, the building trades, the AFL-CIO and the United Auto Workers after replacing Biden at the top of the Democratic ticket.

But the divide within the labor community is a reminder of shifting loyalties in American politics. Democrats have increased their support among white-collar professionals while Republicans try to make inroads among voters who didn't attend college.

During a rally in Michigan on Thursday, Trump claimed that Republicans are now "the party of the American worker," glossing over his anti-union record as president. In a reference to labor unrest at the country's ports, he insisted that "under my leadership Americans won't have to go on strike for a better wage or a better life."

Trump is heading to Georgia on Friday to appear with Gov. Brian Kemp, the latest sign that he's patched up his rocky relationship with the top Republican in a key battleground state. Later in the day, he's holding a campaign event in Fayetteville, North Carolina.

Union voters have traditionally leaned toward Democrats, with 56% supporting Biden in 2020. But Trump has pushed hard to win over blue-collar workers traditionally represented by some of the biggest unions. He won 62% of white voters without college degrees -- though only 24% of non-white voters without college degrees -- in 2020.

It's frustrating for Democrats, who point to the White House's firm support for unions. Biden even joined a UAW picket line last year.

Lisa Anderson, 59, drove more than an hour from Green Bay in her green "AFSCME for Harris-Walz" shirt to hear the vice president speak Thursday in Wisconsin.

She's been an elementary school administrative assistant for 17 years, and she's confident that Harris' union support runs deep.

"I'm not worried about it," Anderson said. "If you're voting for Trump, how can you believe in unions?" AFSCME is the American Federation of State, County and Municipal Employees.

Labor relations could have been a dominant issue in the closing weeks of the presidential campaign if the dockworkers strike continued, leading to snarled ports and shortages on store shelves.

Biden expressed satisfaction that a deal was being worked out.

"We've been working hard on it," he said at the White House. "With the grace of God, and the goodwill of neighbors, it's gonna hold."