It is widely held that when the names go into the hat for the 2016 Democrat presidential primary, only one will matter: Hillary Clinton.
Yet some in her party hope the frontrunner could again be upset by a challenge from an outsider - and their preferred candidate appears to be the liberal senator from Massachusetts, Elizabeth Warren.
In its latest cover story, the political magazine New Republic suggests a Warren presidential run would be "Hillary's nightmare", and describes Senator Warren as "the probable face" of a progressive "insurgency".
Warren, 64, has made her name as a critic of the financial industry. Clinton is thought of as being sympathetic to Wall Street; her husband presided over widespread deregulation while in the White House.
If the issue remains at the forefront of voters' minds by 2016, the magazine argues, activist enthusiasm for a Warren candidacy could spread. The publisher of the liberal blog Daily Kos, Markos Moulitsas, told the New York Times: "[Warren] is reshaping the Democratic Party and leading its charge toward a more economic populist orientation."
Democrat Bill de Blasio's recent victory in the New York mayoral election, on a platform of correcting income inequality, has also emboldened grassroots Democrats. The co-founder of the Progressive Change Campaign Committee, Adam Green, told the New Republic his fellow progressives were yet to be sold on the predicted Clinton candidacy. "There's very much a wait-and-see approach to Hillary among progressives. It's mutually exclusive to be a real hero for reform and accountability and to have a [fundraising] strategy that relies on Wall Street."
Disillusionment with the financial system led in part to the present fissure between mainstream Republicans and the Tea Party. Less well documented is the narrower split between populist Democrats and their colleagues, seen in the bumper stickers declaring, "I'm from the Elizabeth Warren wing of the Democratic Party".
Originally from Oklahoma, Warren was previously a Harvard Law School professor specialising in bankruptcy law. After the financial crisis, as an adviser to the Treasury Secretary, she was instrumental in the creation of the Consumer Financial Protection Bureau. Last year, she challenged Republican incumbent Scott Brown for the Massachusetts Senate seat. Upon her election, she was asked to serve on the Senate banking committee. One leading financier told the New York Times that her appointment caused "widespread terror" on Wall Street.
The senator's camp has insisted she will not seek the presidency, and she was recently among a group of Democrat woman senators urging Clinton to run. Early polls show Clinton streets ahead of her rivals, with a 48-point lead over Warren in Iowa, and a 53-point lead in New Hampshire. Ed Rendell, former Democrat Governor of Pennsylvania, dismissed the notion that Warren could be the nominee. "If Hillary's in the race, she has zero chance," he told CNBC.
Warren declined to be drawn by the magazine on whether she was mulling a run in 2016. "You've asked me about the politics. All I can do is take you back to the principle part of this. I know what I am in Washington to do: I'm here to fight for hardworking families."