She is one of the most active — and most partisan — senators in the chamber, which is part of what makes Sen. Elizabeth Warren so attractive to the progressive groups pleading with her to enter the 2016 presidential race.
The freshman senator has amassed a solidly liberal record, but it’s the issues on which she has taken the lead that are winning over the Democratic Party’s left wing, who say she is a fighter more than anything else. She organized a rebellion, although it was quickly snuffed out, against loosening Wall Street regulations as part of the omnibus spending bill.
For many on that left wing, her eagerness to fight large banks and corporations is reason enough to demand that she enter the presidential race, if only to give former Secretary of State Hillary Rodham Clinton a reason to remember her party’s liberal flank.
“I don’t think it would be helpful or healthy for our Democratic candidate to not have to go through the sharpening process of a primary, where she could sort of just walk into the general without having committed to some important, real, real economic populism,” Rep. Keith Ellison, Minnesota Democrat and co-chairman of the Congressional Progressive Caucus, said on a recent telephone conference call sponsored by pro-Warren group Democracy for America.
In her short time in office, Ms. Warren has championed a measure that would increase taxes on the wealthy to pay for student loan debt while actively backing liberal causes such as expanding Social Security.
GovTrack.us put her in a tie for the least bipartisan senator in 2013 in terms of co-sponsoring bills introduced by non-Democrats, even as she joined in sponsoring 166 bills or resolutions, tied for second among Senate freshmen.
Progressives say they admired her work well before she won her Senate race in Massachusetts in 2012, ousting tea party darling Sen. Scott Brown. They cite her work as a Harvard law professor or her advocacy for the Consumer Financial Protection Bureau, a government watchdog set up in the wake of the 2008 Wall Street collapse.
“When she was a law professor, she focused on bankruptcy issues, how big banks and corporate interests were really sticking it to the middle class,” said Nick Berning, communications director for MoveOn.org, which, along with Democracy for America, is working to draft her into the presidential race.
Once in the Senate, Ms. Warren picked an early fight with the Obama administration over the president’s flirtation with limiting the growth of Social Security benefit increases by using a different formula to calculate cost-of-living hikes.
She said the “chained CPI” was “just a fancy way of saying ‘cut benefits,’” and her stance solidified her bona fides with liberal groups.
“Because she’s from Massachusetts, she can say almost anything safely,” said Samuel L. Popkin, a political scientist at the University of California at San Diego and author of “The Candidate: What It Takes to Win — and Hold — the White House.” “She’s speaking to a very vocal, active slice of America.”
Her fights have both irked and intrigued Republicans, who have watched her battle fellow Democrats.
“We’re going to learn what kind of warrior she can be — no doubt that she believes what she says,” said Republican Party strategist Mike McKenna.
Mr. Berning said MoveOn’s interest in recruiting Ms. Warren isn’t a campaign against Mrs. Clinton or any other candidate, but instead is a push to make sure the ideas Ms. Warren advances are part of the Democratic primary discussion.
Mrs. Clinton still has overwhelming leads in early polling for the Democratic presidential primary race, running 40 to 50 points ahead of Ms. Warren in some polls.
At this stage of the 2008 electoral cycle, however, polling of Democratic voters looked similar. Mrs. Clinton was the overwhelming and seemingly inevitable choice over Barack Obama, John Edwards and a host of other figures.
Ms. Warren has said repeatedly that she is not running for president, and her office did not to respond to requests for comment.
Her most recent push was an ultimately unsuccessful effort to oppose a provision in the $1.1 trillion 2015 spending bill that allows banks to trade derivatives with federally insured money.
Ms. Warren took to the Senate floor to single out and attack Citigroup, accusing the company of an “unprecedented” grip over economic policymaking in the executive branch, pointing to the bank’s ties to recent administrations and the Obama administration.
She said the Dodd-Frank reform law should have gone further and “broken you into pieces.”