Sen. Elizabeth Warren (D-Mass.) is becoming a power player in Democratic politics, starting with her rapid emergence as a fundraising juggernaut. She raised $1.6 million through late April in support of nearly two dozen Senate contenders and her home state House delegation through emails, fundraising events, and checks cut by her leadership committee, PAC for a Level Playing Field.

Last weekend, in a typically colorful email for Arkansas Sen. Mark Pryor, Warren said she had once taught his opponent at Harvard. "Tom Cotton was a fine student in the classroom, and he earned a passing grade. But he is flunking the people of Arkansas in the United States Congress," she wrote of the 37-year-old freshman House member.

Warren's Midas touch with money is only one aspect of her clout. She is also a font of strategically useful policy ideas and, in the largest sense, she is True North for liberals. Those multiple roles make her invaluable to Democrats — and at the same time, foreshadow how awkward things could get in 2016, whether she's part of the presidential field or a looming, potentially overshadowing figure on the sidelines.

Democrats are always in a tough spot as champions of the underdog who must also maintain ties with the business and financial communities that are the wellsprings of jobs and investment, not to mention campaign contributions. Warren, with her aggressive challenges to investors, bankers, regulators, and anyone else she sees as perpetuating a game rigged against consumers and people on the economic brink, is a constant source of pressure on other Democrats to move in her direction.

Sometimes her outsized influence is political gold. There is no more vivid example of the Democrats' "we're on your side" pitch than the Consumer Financial Protection Bureau, which Warren proposed as a Harvard professor and oversaw at its launch after Congress created it. Her latest policy crusade is another political winner for Democrats — a Senate bill allowing people with high-interest student loans to refinance at a rate under 4 percent.

Warren's impact is already apparent in a 2016 presidential race that hasn't officially started yet. Hillary Clinton represented the financial sector as a senator from New York, but, perhaps sensing where the populist winds are blowing these days, she sounded a lot like Warren last week in a speech at the New America Foundation. The undeclared, undecided frontrunner talked of the fading "dream of upward mobility" and the "wake-up call" of statistics showing that middle-class Canadians are doing better than middle-class Americans. She said regulators during the George W. Bush administration had "allowed the evolution of an entire shadow banking system that operated without accountability." She even said that "some" are calling our economic times "a throwback to the Gilded Age of the robber barons."

Whether Warren runs for president or not, and regardless of how her fundraising power moves the needle for candidates she helps, this rhetorical shift is what makes Warren the 2016 X-factor. She may well pressure more centrist, arguably more "electable" Democrats to be more confrontational on economic fairness issues, much as the Tea Party has pushed establishment Republicans to be more aggressive on guns, immigration, and other issues. And Warren-style rhetoric could win someone the Democratic nomination.But how would it play in a general-election campaign? And would it scare off big-money donors?

Democrats have long counted on the titans of finance for a certain level of largesse. President Obama raised $43.7 million from the finance, insurance, and real estate industries in 2008, according to the Center for Responsive Politics, although he was making clear in campaign speeches that he wanted to regulate them more tightly. In 2012, after he had followed through by signing the Dodd-Frank and health-reform laws, contributions from these industries declined by more than half — but still amounted to $20.4 million. Even Warren managed to raise $1.4 million in her 2012 Senate race from the finance, insurance, and real estate industries.

But Wall Street and its allies could just as easily turn their money against a Democrat they perceived as an antagonist. A wealthy individual determined to influence the outcome of an election could spend tens of millions of dollars against a threatening populist candidate or on behalf of someone like New York Gov. Andrew Cuomo, whose liberal social achievements (same-sex marriage and tighter gun safety laws among them) are accompanied, some would say outweighed, by his tax cuts for corporations and the wealthy.

In the end, though, Warren is likely to be a positive for Democrats in 2016. Her ability to energize donors and activists is a huge plus. And she is a team player, as her email for Pryor suggests. Pryor is nobody's idea of a liberal — in fact, he was the only Senate Democrat who voted in April 2012 to block the Buffett rule, which would have made sure millionaires paid an effective income tax rate of at least 30 percent. Warren was not in the Senate then, but she is a fan of the principle. As she pushes to reduce student-loan interest payments, she wants to offset the government's lost revenue by passing... you guessed it. The Buffett rule.

Warren is also encouraging a Clinton presidential bid and says repeatedly that she herself is not running. She calls Clinton "terrific" and has avoided criticism of Clinton, even when she’s asked point-blank about negative things she has said about her in the past. For a public figure as outspoken as Warren, that is the ultimate demonstration of team spirit.