The union's support is key because it promises organizing muscle across the country. Sanders says that if turnout is high for Monday's leadoff Iowa caucuses, he will win — and he believes a win there will propel victories in the next two states that vote, New Hampshire and Nevada.
“As with 2016, once again the Sanders campaign is boldly uplifting the goals and aspirations of workers," union president Mark Dimondstein said in a statement. “Simply put, we believe it is in the best interests of all postal workers, our job security and our union to support and elect Bernie Sanders for president.”
Unions wield influence in the Democratic primary, though many have yet to pick sides in the still-crowded 2020 field. The National Nurses United backed Sanders in November after endorsing him in 2016.