WASHINGTON, D.C. - Former Vice President Joe Biden officially kicked off his 2020 presidential campaign rallying union workers in Pittsburgh on Monday. This was his first official campaign stop after announcing his bid on Thursday.

At a Pittsburgh union hall, the man known as “Middle-Class Joe” harkened back to the Democratic Party’s roots, promising to fight for workers’ rights, a $15 minimum wage and close corporate loopholes.

“We’re going to change that so millionaires and billionaires don’t pay lower taxes than firefighters and teachers and I could go on and on. We need to reward work in this country, not just wealth,” Biden said to a crowd estimated at 600 people.

Biden, 76, built upon some early endorsements, now with his biggest yet – from the nation’s largest firefighters union, the International Association of Fire Fighters, which has more than 300,000 members. That includes nearly 140 City of Erie firefighters) who are now backing Biden.

“We need Joe Biden to help workers, to help the middle class,” said Greg Laird, secretary of IAFF Local 293 in Erie.

“He knows that labor and unions built the middle class, they built this country,” said IAFF President Harold Schaitberger, who led into Biden’s rally.

Courting those middle class and working-class voters is what brings biden to Western Pennsylvania. In 2016, then-candidate Donald Trump took Pennsylvania and its traditionally Democratic, union-heavy strongholds like Erie County and Luzerne County, from two-to-twenty percent respectively.

It’s a move that Erie-area labor leaders are noticing, even with the election still 18 months away.

“Some people possibly got forgotten along the way,” said Bill Panitzke, business agent for Steamfitters Local 449, a group that supports but has not formally endorsed Biden. “But I think they’re possibly coming back to the labor side of things.”

We found one of those voters outside the union hall. Bobbie Hartley, 60, was an Obama voter turned Trump supporter in 2016. She is currently undecided, now looking for a candidate who will focus on protecting Social Security and Medicare.

“I don’t know who I’m going to vote for,” Hartley said. “I won’t know probably until the week of the election.”

What makes Biden’s stop in Pittsburgh even more significant: Pennsylvania is not an early-primary state, like Iowa where he stops on Tuesday. Analysts believe it’s a clear push to win back the battleground state, and the voters who left his party nearly three years ago.