During the first presidential debate, President Donald Trump falsely claimed that the sheriff in Oregon endorsed him.
The Massachusetts senator is the last of Biden's major Democratic rivals to endorse him, holding out longer than fellow progressive Sen. Bernie Sanders.
"He’ll show there’s more that unites us than divides us," the New Jersey Democrat, who quit the presidential race in January, said of Biden.
Rep. Devin Nunes’ hometown paper scorched his “obsession” with Donald Trump and endorsed his Democratic challenger in the 2020 elections.
Castro, who quit the Democratic race this month, said Warren is "unafraid to fight like hell to make sure America’s promise will be there for everyone."
On Saturday, the unions will host a televised public education forum for Democratic candidates, culminating a rigorous endorsement process.
Marie Newman, backed by the high-profile progressive lawmaker, is going after conservative-leaning Rep. Dan Lipinski in Illinois.
The Working Families Party endorsed Sen. Bernie Sanders (I-Vt.) in the 2016 election cycle.
Sanders has "the spine" to confront income inequality and the corrupting effect of money, said Ellison, a former co-chair of the Congressional Progressive Caucus.