Prediction: If Elizabeth Warren runs for president, she will get a lot of votes in a Democratic primary and could force the eventual Democratic nominee to the left, the way Newt Gingrich, Rick Santorum, et al did to Mitt Romney in 2012.

Sen. Elizabeth Warren's rousing speech Sen. Elizabeth Warren (D-MA) (Pete Marovich/Bloomberg)

The Massachusetts senator gave a rousing speech to the AFL-CIO Sunday and she offered liberals some rhetorical meat served raw, the way they like it.There has always been a powerful strain in Democratic presidential politics, called “liberal” or “populist” or “progressive,” which, whatever its precise ideological compass readings, is anti-establishment. Gene McCarthy started the trend, and it continued: George McGovern in 1972; Gary Hart against Walter Mondale in 1984; Paul Tsongas in 1992, Bill Bradley in 2000 and Howard Dean in 2004. These candidacies attracted a core of supporters, usually whiter and more upscale economically than the average Democratic primary voter, and they racked up some electrifying wins or narrow losses before running out of gas. One could also argue that two anti-establishment candidates actually won the Democratic nomination, Jimmy Carter in 1976 and Barack Obama in 2008, but I would point to extraordinary circumstances: Watergate in the 1976 race and the Iraq was and the historic nature of Obama’s candidacy in 2008.

Does 2016 offer the kind of extenuating circumstances that could propel an anti-establishment candidate beyond a disruptive force into a victorious one? One criteria for dramatic political upheaval seems in full bloom: a weak economy with growing income disparity. This is a backdrop as volatile as Watergate and Iraq, and both parties show deep signs of unrest. We see a full-blown anti-establishment movement on the Republican side: First, the tea party and now its progeny who comprise much of the 2016 Republican field: Rand Paul, Ted Cruz and Marco Rubio. The Democrats’ “mad as hell” movement has been more muffled so far, but you hear its beat in opposition to intervention in Syria and in the perception among liberal Democrats that Obama caved to corporate interests on financial reform and health care. It is this strain that cheers Warren and creates an opening for a “people not the powerful” message in 2016 on the Democratic side.