From a glowingly positive front-page New York Times article about Elizabeth Warren:
in seizing on issues animating her party's base — the influence of big banks, soaring student loan debt and the widening gulf between the wealthy and the working class — Ms. Warren is challenging the centrist economic approach that has been the de facto Democratic policy since President Bill Clinton and his fellow moderates took control of the party two decades ago.
If you are a left-wing New York Times editor or reporter, the "raise taxes on the rich" approach of first-term Bill Clinton, Al Gore, John Kerry, and Barack Obama looks "centrist." I mean, maybe one can make an argument that these guys were more centrist than Maxine Waters, Dennis Kucinich, or Bernie Sanders, but that's an argument, not a flat-out statement to be made as context in a news article. These Democrats may look centrists compared to the extreme-hard-left of their own party, but compared to centrist Republicans, they look like leftists. It's a framing issue, and the frame the Times chooses here gives the Democrats the centrist stamp of approval.