WASHINGTON -- Elizabeth Warren's campaign for U.S. Senate received a major endorsement on Tuesday, picking up the support of former Wisconsin senator Russ Feingold. It's Feingold's first Senate endorsement of the 2012 election season and a clear indication that Warren's race will be a top priority for progressives around the country.
In an email scheduled to be sent Tuesday morning, and provided to The Huffington Post by Feingold's staff, Feingold calls support for Warren's campaign "an absolutely crucial part of our fight against the nasty influence of corporate money in politics."
"Elizabeth has fought for years to rein in Wall Street and protect the middle class," writes Feingold in the email to backers of Progressives United, his political action committee.
"In 2005, she stood up against the Wall Street wish list of a bankruptcy bill -- a huge corporate giveaway I opposed in the Senate. And after the big banks drove us into a recession, Elizabeth proposed a new Bureau of Consumer Financial Protection, and then fought tirelessly to make sure the Obama administration created it. So when Elizabeth announced her decision to run for the U.S. Senate in Massachusetts this month, to keep fighting for middle class families on Capitol Hill, I couldn't have been happier."
Feingold even hints that Warren may be the best person to carry on his legacy in the Senate.
"In all my years in the Senate, I always took positions that I believed in, even when my own party tried to stand in the way," he writes. "I know Elizabeth will be exactly the same kind of senator."
He then calls on the email's recipients to donate $5 before Warren has to submit her first public financial data on Friday, which will show how much she has raised.
Warren is the Democratic frontrunner to unseat Sen. Scott Brown (R-Mass.), although she faces several primary challengers.
The national Democratic Party has insisted it's neutral in the primary in the race, but based on the number of emails sent out about Warren as opposed to the other candidates, it's seems clear who officials are pushing for.
Feingold's endorsement gives perhaps the strongest signal yet that Warren's race is also a top priority for progressive leaders, and the nod could likely lead to a surge of online donations from around the country.
It's also building on a progressive anti-Wall Street movement that has been growing, as Politico's Ben Smith has pointed out.
Feingold has long been an advocate for strong Wall Street reform and cleaning up corporations -- he opposed the Dodd-Frank legislation because it didn't go far enough and called on Democrats to stop taking corporate contributions. Warren has been called "Wall Street's worst nightmare" for building the Consumer Financial Protection Bureau.
Progressives United also recently backed the New York Attorney General Eric Schneiderman (D), a public official who is becoming a favorite of progressives for his push to hold banks liable for claims that they illegally foreclosed on American homeowners.
Last month, Feingold announced that he would not be seeking elected office in 2012, dashing the hopes of many progressives who were hoping to see him run for Senate again or even challenge Wisconsin Gov. Scott Walker (R) in a possible recall election.
Feingold's PAC and his affiliated nonprofit aim to mitigate the effects of -- and eventually overturn -- the Supreme Court's Citizens United decision. It has launched advocacy campaigns calling out corporate corruption and given money to progressive candidates, but the Warren announcement is the first actual endorsement.
According to a recent survey by Public Policy Polling, Warren narrowly leads Brown, 46 to 44 percent.