PORTLAND, Maine — Troy Jackson was a longtime labor activist and logger before he unexpectedly became the Democratic nominee for U.S. Senate in Maine. On Monday, he returned to a union hall to tell workers they need to go to the polls this fall — to raise the minimum wage, expand family medical leave and show support for one another.

“Labor Day has never been just another holiday,” Jackson told several hundred union members at a Southern Maine Labor Council event Monday in Portland. “Today, here with the people I’ve fought alongside for years, I want to make a pledge about exactly what I’m going to do in the United States Senate.”

Jackson, who became the nominee in a special convention in July, is trying to whip up support in a short period of time as he attempts to unseat longtime Republican Sen. Susan Collins in a race Democrats view as critical to winning Senate control.

He was among the candidates in key November races who spent Labor Day weekend stumping at festivals, union halls and parades as the midterms enter the final weeks with control of the House and Senate on the line.

This year’s campaigns already have been combative, busy and expensive, and they are expected to get even more so as a larger number of voters tune in ahead of the Nov. 3 general election. The first statewide mail ballots already went out, in North Carolina, on Friday.

Outside the Jackson event in Portland, Doug Born, a 64-year-old union stagehand from Westbrook, said Jackson’s background as a logger and his longtime support of organized labor are reasons to support him.

“I think he’d be the most working-class guy in the Senate. That appeals to me,” Born said. “We need more union members in seats of power.”

Collins had no events scheduled for Labor Day, but she visited shipbuilder Bath Iron Works early in the morning on Sept. 1 to greet employees and promise to continue “leveraging her seniority to secure billions in destroyer contracts, infrastructure modernization, and wage enhancements,” a spokesperson said in a statement.

President Donald Trump is also stepping up his own efforts for Republicans in the coming days. His party is set to gather this week in Dallas for an atypical midterm convention, a two-day event that Trump and other Republicans hope will generate enthusiasm for the GOP, which currently controls the White House and Congress.

Typically, the party in power in Washington loses seats in Congress during the midterm elections.

Trump has vowed to campaign for Republicans in dozens of races, saying he plans to spend the 30 days before Nov. 3 stumping in House and Senate battlegrounds.

Georgia Sen. Jon Ossoff and Democrats’ nominee for governor, Keisha Lance Bottoms, both visited an AFL-CIO picnic in metro Atlanta. Ossoff, the only Democratic senator seeking reelection in a state Trump won in 2024, praised current and former labor leaders and activists, while lamenting workers’ economic circumstances under a billionaire president.

Ossoff is facing Republican Rep. Mike Collins, who owns a trucking company but has pitched himself as a working-class advocate. Collins’ campaign did not respond to an inquiry about his Labor Day plans.