Hillary Clinton with her running mate, Sen. Tim Kaine; her husband, former president Bill Clinton; and Kaine's wife, Anne Holton, at a Friday rally at Temple University in Philadelphia. (Andrew Harnik/AP)

JOHNSTOWN, Pa. — On the second day of their bus tour through Pennsylvania and Ohio, Democratic presidential nominee Hillary Clinton and her running mate, Sen. Tim Kaine (Va.), moved deep into potential Donald Trump country.

The pair toured an advanced manufacturing plant in the rural, white countryside of central-western Pennsylvania and were holding rallies in Pittsburgh and in Youngstown, Ohio.

The bus trip is meant to highlight Clinton’s pledge to add new jobs, raise wages and promote homegrown manufacturing. All three are issues of acute concern to middle- and working-class voters, many of whom are white and increasingly accustomed to voting Republican — a trend Trump is counting on in his bid to reach the White House.

In Pittsburgh, Dallas Mavericks owner and Pittsburgh native Mark Cuban endorsed Clinton and told his story of failing at several jobs before starting a series of successful companies.

Cambria County, home of the Johnstown Wire Technologies plant that Clinton and Kaine toured Saturday, is about 90 percent white with a median household income below $50,000. Mitt Romney won the rural western Pennsylvania county in 2012. Barack Obama won it in 2008, George W. Bush in 2004 and Al Gore in 2000.

As it approached the old factory, Clinton’s bright blue bus — which her campaign made sure to tell reporters was made in America — rolled past a small but loud group of Trump supporters holding campaign signs and chanting on the roadside in a lashing rain.

“I’m an optimist, and I’m confident,” Clinton told the crowd of mostly unionized factory workers inside. “And I think if you look at the history, that’s how we get things done. It’s not the whiners and the complainers and the insulters who move our country forward,” she said to applause. “It’s the workers and the builders. It’s people who get up every day and try to figure out how it’s going to be better for them and their families.”

That Pennsylvania is considered a presidential battleground state is a testament to the demographic and political shifts Trump intends to exploit. The state has voted Democrat in each presidential election from 1992 forward, including for both terms of President Bill Clinton, based largely on Democratic strength in cities and union households.

Clinton is accompanying his wife on the bus tour, which echoes the heartland trip he took with Gore upon winning the Democratic nomination in 1992. Seated to one side of his wife as she spoke, Clinton obligingly opened his jacket to flash his casual shirt when she noted that unlike many Trump-branded products, his was made in the United States. In Reading, Pa., no less, Hillary Clinton pointed out.

“You truly are the reason I have so much confidence that America’s best days are still ahead of us,” Clinton said. “It’s in stark contrast to the vision that Donald Trump is laying out, because I don’t think we’re weak. I don’t think we’re in decline. I think we can pull together because we are stronger together.”

In a statement, the Republican presidential nominee's campaign ridiculed Clinton's swing through Pennsylvania, noting that the Johnstown region had lost a significant number of manufacturing jobs since the North American Free Trade Agreement took effect during Bill Clinton's presidency.

"Hillary Clinton visiting Johnstown, Pennsylvania, is like a robber visiting their victim," said Stephen Miller, who advises Trump's campaign.

Jose A. DelReal in Washington contributed to this report.