New York Gov. Andrew Cuomo faces a challenge in his bid for a second term in the Democratic primary as he seeks to dispatch liberal activist Zephyr Teachout.

With Teachout largely unknown to many voters, Cuomo is widely expected to win. But Teachout’s presence on the ballot nonetheless serves as a liberal referendum on the popular incumbent, and highlights Cuomo’s uneasy relationship with his party’s base. It could upend his goal of winning re-election by overwhelming margins.

Teachout, a Fordham University law professor and former director of the good-government Sunlight Foundation, has criticized Cuomo for his support for business-friendly tax cuts, while saying he hadn’t done enough to address government corruption and income inequality.

Cuomo spent most of the primary race publicly ignoring Teachout, refusing multiple requests to debate her and holding few campaign events. His campaign sought to kick Teachout off the ballot by challenging her New York state residency, a legal maneuver that many observers say backfired by giving Teachout’s campaign greater exposure.

While she claimed endorsements from the Sierra Club, the National Organization for Women and New York’s second largest state-employee union, Teachout was unknown to most voters. Cuomo’s campaign won support from other unions and political heavyweights like Hillary Clinton and New York City Mayor Bill de Blasio.

Supporters defended Cuomo’s liberal credentials throughout the campaign, noting his work to pass same-sex marriage and gun control measures while also working to cut state government dysfunction and boost the economy through business-friendly tax policies and initiatives designed to spur economic development in western New York.

Also on the ballot Tuesday are Cuomo’s running mate, former Buffalo congresswoman Kathy Hochul, and Columbia University law professor Tim Wu, Teachout’s choice for lieutenant governor.

The November ballot will feature Republican Rob Astorino, the Westchester County executive, and Green Party candidate Howie Hawkins.

Polls close at 9 p.m.

(AP)