The left's quiet advance in Democratic primaries

National liberals point to a handful of recent contested primaries where candidates from the party’s “Elizabeth Warren wing” beat moderate “corporate Democrats” to argue that the left wing is on the rise. It’s a similar dynamic to the Tea Party-vs.-establishment divide on the right, though far less divisive, and a trend that has the potential to quietly reshape the Democratic Party if it continues.

In New Jersey, Bonnie Watson Coleman, a former assemblywoman who campaigned on raising taxes on millionaires to spend more on education, had been thought to be in a close race with a moderate state senator, Linda Greenstein. Instead, Coleman won the primary by a double-digit margin.

In Iowa, Pat Murphy, a former state representative, aired TV ads that dubbed him a “bold progressive.” He beat out four opponents, taking 37 percent to his nearest competitor’s 24 percent.

Victories like these have led the Progressive Change Campaign Committee to declare vindication for its view that Democrats win when they campaign on a platform of muscular liberalism.