White working-class union voters were divided on Biden in 2020, but some union leaders say he now has their support.
Some building trades unions, whose members traditionally vote Republican, did not endorse any candidate in 2020 after local leaders couldn't agree over backing Biden or Donald Trump.
"There is not one labor leader worth their salt in Philadelphia that hasn't recognized just how much President Biden has supported men and women in labor.
Biden won 57% of union households nationwide in 2020 compared with 40% for Trump, according to Edison Research.
In December, some unions criticized Biden for signing legislation preventing a nationwide rail strike.
Persons:
Joe Biden, Biden, Kamala Harris, Trump, couldn't, Donald Trump, Ryan Boyer, wasn't, Seth Harris, Harris, Nandita Bose, Jarrett Renshaw, Heather Timmons, Bill Berkrot
Organizations:
AFL, CIO, Biden, Republican, boilermakers, steelworkers, Union, Democratic, Trump, Edison Research, United Auto Workers, Northeastern University, White, Thomson
Locations:
Philadelphia, Washington, Pennsylvania, Wisconsin, Michigan, Michigan , Wisconsin, Georgia, Arizona