Sen. Elizabeth WarrenElizabeth WarrenWarren on attending Trump’s inauguration: ‘I wanted it burned in my eyes’ Maher on Obama speaking fee: Isn’t that what cost Clinton the election? Presidents with the worst first 100 days MORE (D-Mass.) says she is not running for president in 2016.
But that hasn't squashed liberals' hopes. Warren remains in second place among Democrats in most 2016 polling of early caucus and primary states such as Iowa and New Hampshire. A Bloomberg/Des Moines Register poll released Tuesday among likely Democratic caucus-goers in Iowa put former secretary of State Hillary Clinton way out front with 53 percent support and Warren a distant second at 10 percent.
But here are five scenarios that might prompt Warren to change her mind:
1.) A formidable progressive challenger to Hillary Clinton doesn't emerge. Sen. Bernie Sanders (I-Vt.), Vice President Biden and Maryland Gov. Martin O'Malley are often listed as Democratic alternatives to the all-but-declared Clinton candidacy. But none has Warren's star power among the progressive base.
Liberals have long criticized the Clintons for their close ties to Wall Street, and the flipside of that populist passion — an ardent admiration of Warren’s combative attitude to big business — has propelled the rapid rise of the Massachusetts senator.
While Sanders has indicated he will challenge Clinton, most don't consider him a serious contender.
"The fact is, other than perhaps Vice President Joe Biden, no other major Democratic figure has worked harder or done more this cycle to help Democrats hold the Senate [than Warren]," said one Democratic strategist, granted anonymity to speak more freely.
Robert Borosage, co-director of the liberal Campaign For America's Future, said that Warren could join the race if "Hillary decides to pitch her campaign to the right of Obama."
"[Clinton's] already made it clear that she will do so on foreign policy, and there are rumors that she wants to distance herself from Obama's focus on inequality," said Borosage. "A center-right campaign — center on economy, right on foreign policy — would counter Warren's political project.”
2.) Donors rally behind Warren. Warren has already proven herself to be a prodigious fundraiser. She raked-in $42 million during her 2012 bid to defeat incumbent GOP Sen. Scott Brown in Massachusetts, according to campaign disclosure records.
"The progressive base of the Democratic Party — and its donors — are not convinced that Hillary is the answer in 2016, let alone the future of the party," said GOP strategist Ford O'Connell. "So there is a shred of daylight for Warren to make a serious run at the Democratic presidential nomination in 2016, regardless of whether Hillary is in the race or not."
Borosage said that Warren "won't worry about donors. Her ability to raise money is secure — both large and small donors."
3.) It's now or never. At 65, Warren is only one year younger than Clinton, even though age concerns tend to be raised more often in the latter’s case.
"At 65 years of age, Warren has to be wondering out loud if there will be room for her in the Democratic presidential calculation in either 2020 or 2024," O'Connell said.
Should Warren run for president in 2016 and win, she'd be 67 when taking office. Ronald Reagan was the oldest president to take office: he was 69 when first inaugurated in 1981. Clinton would be 69 at her inauguration should she win the White House in 2016.
If Republicans win the Senate in the midterms, Warren might view running for the White House as more appealing than other plausible longer-term goals such as being appointed to a president’s Cabinet or heading the controversial Consumer Financial Protection Bureau, which many observers acknowledge was her idea.
4.) The economy dips again. Clinton has been tight-lipped about her 2016 economic pitch, but liberals are hoping she'll offer a plan that would expand Social Security and increase big bank regulations. If she doesn't, they hope a Democratic primary challenger would push her to the left.
"Not only are these issues extremely popular among the Democratic base, but they are also key to winning the general election," said TJ Helmstetter, spokesman for the Progressive Change Campaign Committee. "No matter who runs in 2016, they'll need to adopt Elizabeth Warren's economic populist agenda for the middle class."
Erica Sagrans, campaign manager for Ready For Warren, said that if the economy were to decline again, it would only fuel the kind of populist anger that could, in the end, change Warren's mind. Warren herself has frequently declared that the "system is rigged" against middle class Americans.
"An economic dip would only make it more clear that Warren is right — the system is rigged — and people of all political persuasions agree with her," said Sagrans.
5.) Hillary sits it out. If Clinton doesn't run for president, the Democratic field would be wide open and Warren would be a front-runner. "If for some reason former Secretary Clinton does not decide to run, Sen. Warren will be under tremendous pressure from those on the left to put her hat into the ring despite what she’s previously said," said Manley.
"She's identified with a number of high-profile issues that are prevalent today: most notably financial reform and income inequality," said Phil Singer, who worked on Clinton's 2008 presidential campaign. "She'd be able to promote those issues and force the Democratic primary process to focus on those topics.
"That’s the beauty of presidential politics, you never know what random plot twist is going to catapult a random candidate into the spotlight," Singer added.