The warning has ricocheted around the financial world in recent weeks, in conversations at Midtown restaurants and Washington fund-raisers, carrying urgent appeals for money from financial executives around the Northeast: The battle to re-elect Senator Scott P. Brown, the Republican from Massachusetts, just got a little more interesting.  Senator Scott P. Brown, left, a Massachusetts Republican, has drawn support from financial institutions in the Northeast.  “Senator Brown is a free-market advocate who believes that our strength as a nation comes from the ingenuity and hard work of its people,” read an invitation to a fund-raiser at a New Canaan, Conn., country club last week, that circulated among hedge fund and private equity executives. His Democratic opponent, the invitation noted, was all but certain to be the financial industry’s most prominent foe: “big government liberal Elizabeth Warren.”  Mr. Brown, a freshman who harnessed populist Tea Party anger to win the seat once held by Edward M. Kennedy, has taken more money from the financial industry than almost any other senator: all told, more than $1 million during the last two years, according to data from the Center for Responsive Politics.  Of the 20 companies that accounted for the most campaign donations to Mr. Brown, about half were prominent investment or securities firms like Morgan Stanley, Fidelity Investments and Bain Capital. His donors include such blue-chip names as Gary Cohn, the president of Goldman Sachs, and the hedge fund kings John Paulson and Kenneth Griffin.  Mr. Brown, in turn, has been an important ally at critical moments, using his swing vote in the Senate to wring significant concessions out of Democrats on last year’s financial regulation bill, including helping strip out a proposed $19 billion bank tax and weakening a proposal to stop commercial banks from holding large interests in hedge funds and private equity funds.  But the intensity of his relationship with Wall Street was altered in September, when Mr. Brown got a new opponent: Ms. Warren, a law professor and consumer advocate who has described herself as an intellectual godmother of the Occupy Wall Street movement.  Ms. Warren’s relentless manner and withering attacks on predatory lenders have won her enemies from Wall Street to Washington, where as a member of an oversight panel she helped usher in the largest expansion in decades of federal oversight of the financial industry. Now Mr. Brown’s support for the industry — and Ms. Warren’s battles with it — are becoming a defining issue in one of the most hotly contested Senate races and a magnet for special interest money.  “It’s shaping up as a sort of proxy war in the long-running debate over regulation in American life,” said Travis Plunkett, legislative director of the Consumer Federation of America, which has lobbied hard for more regulation of banks. “It’s the mere fact of her existence in the race, simply because she’s sketched out a strong position and is effective.”  Mr. Brown’s relationship with the financial industry owes in part to circumstance. He is one of few Republican senators in a region that is home to the nation’s most important financial centers, providing an open door and friendly ear to a executives who often lean Republican in their political giving but whose representatives in Washington are predominantly Democrats.  And his record on Wall Street issues is hardly one-sided: He provided the crucial 60th vote needed for the financial overhaul, known as Dodd-Frank, which Ms. Warren praised as “the strongest set of financial reforms in three generations” when it passed. And Mr. Brown angered banks in June when he voted against a measure that would have delayed a rule restricting billions of dollars in fees that banks charged merchants for debit card transactions.  But Ms. Warren’s advocacy for tighter financial regulation is so widely abhorred by Wall Street executives, some said, that lingering annoyance over Mr. Brown’s occasional heresies is rapidly evaporating.  “It’s not even about Scott Brown,” said one Wall Street executive, who asked for anonymity to discuss private discussions with his colleagues about the race. “It’s about: Do you want Elizabeth Warren in the Senate?”  Ms. Warren has aggressively promoted her credentials as a defender of the middle class and scourge of the financial industry, boasting in her first television ad that she “worked to expose how Wall Street and the big banks are crushing middle-class families.”  This week, a new union-backed independent expenditure group, Rethink PAC, unveiled ads casting Mr. Brown, the onetime Tea Party populist, as a hypocrite for his ties to Wall Street.  Mr. Brown has emphasized his breaks with the industry, including his call this week for an up-or-down Senate vote on President Obama’s nominee to head the new Consumer Financial Protection Bureau, which Ms. Warren was once the administration’s designee to head.  Edward Wyatt contributed reporting from Washington.
Senator Scott P. Brown of Massachusetts, a leading fund-raiser in the financial industry, is expected to face Elizabeth Warren, a strong proponent of regulation, next year.