Other labor leaders, while citing shortcomings of the Obama presidency, say Mr. Biden was an advocate for their interests within the administration. Teachers’ unions were furious after Mr. Obama publicly embraced the firing of the entire faculty of an underperforming school in Rhode Island in 2010. But Randi Weingarten, the president of the American Federation of Teachers, said Mr. Biden helped resolve the situation.
“We started having a fairly heated argument, me and the vice president, at an A.F.L. meeting,” Ms. Weingarten said. “But he heard what I was saying.”
Jared Bernstein, an economic adviser to Mr. Biden during his vice presidency, said the same was often true on trade and other issues, including labor-law reform, which faced a complicated path in the Senate. “I know for a fact where Biden is on these things,” Mr. Bernstein said. “But he was part of an administration that at times very much pleased the unions, and at other times very much pissed them off.”
(As a senator, Mr. Biden supported some free-trade legislation, like the North American Free Trade Agreement.)
But many labor officials regard Mr. Biden as essentially a sympathetic face for unfriendly policies he was either powerless to reverse or personally advanced. One cited Mr. Biden’s role in leading the negotiations with Republicans over a long-term deficit-cutting deal that could have led to cuts in programs like Social Security and Medicare.
Mr. Biden, whose record on Social Security has been a subject of sparring with the Sanders campaign, says he supports an expansion of benefits for many retirees.
Frank Flanders, the political director of the food workers’ local in Ottumwa, said that he was skeptical of Mr. Biden’s views on trade and his more hawkish foreign policy views, and that he regarded Mr. Biden as a “corporate Democrat.”
“I think we had a lot of Trump voters in the general, for the most part it’s because he wasn’t Hillary,” said Mr. Flanders, describing how his members voted in 2016. “It’s also a concern I have about a Biden candidacy.”