Sen. Michael Bennet (D-CO) was thought to be a shoo-in for Colorado’s Democratic primary for governor. But on the eve of the election, the well-known senator and 2020 presidential candidate found himself in a “toss-up” race against Colorado Attorney General Phil Weiser.

With the seat solidly in the Democrats’ court, the real fight is the Tuesday primary. It presents the latest high-profile showdown in the party between a more establishment candidate, Bennet, and someone who’s positioned himself as the insurgent outsider, Weiser.