Elias Isquith describes how the Democratic Party has moved left (boldface mine):
Of course, as encouraging as Emanuel’s stumble is to the left wing of the Democratic Party, it’d be the height of folly to declare victory over the “third way,” neoliberal approach just yet. Emanuel is quite likely to defeat Garcia now that the two are going one-on-one. And protest votes can have a way of making people think the battle’s been won, when in truth it’s only just started. Nevertheless, if we pair Emanuel’s hollow victory with other recent, successful campaigns from the left — like Sen. Elizabeth Warren’s thwarting of the Antonio Weiss nomination, or Zephyr Teachout’s humbling of Gov. Andrew Cuomo — it’s hard to deny that there’s a change happening within the Democratic base.
And for their own sake if nothing else, Hillary Clinton and the other national leaders in the Democratic Party would be wise to pay it attention.
I don’t really think it’s a change in the Democratic base. Instead, Democratic politicians have begun to realize there’s a market for left-leaning political ideas (and ideals). I haven’t changed that much in the grand scheme of things, but twenty years there really weren’t other options in many parts of the U.S. to the Clintonian New Democrat. What you’ll note–and Isquith doesn’t–is that each of these pocket rebellions coalesced around a political figure.
To me, the interesting question is why are Democratic politicians starting to move to the left of Rockefeller Republicanism.