FILE – President Joe Biden speaks during a meeting with his “Investing in America Cabinet,” in the Roosevelt Room of the White House, Friday, May 5, 2023, in Washington. (AP Photo/Evan Vucci, File)

WASHINGTON (AP) — Joe Biden opened his 2020 presidential run at a Pittsburgh union hall. The first political rally of his reelection campaign is being held at a union gathering on the other side of Pennsylvania, punctuating just how much the president is counting on labor support to carry him to a second term. The symmetry is no accident. Rallying labor activists on Saturday at Philadelphia’s Convention Center can help Biden’s campaign ignite early enthusiasm — and organizing muscle — that may eventually boost Democratic voter turnout in the city’s fast-growing suburbs and other key parts of battleground Pennsylvania, which in 2020 helped him flip the state four years after it backed Donald Trump.