Former Rep. Tom Perriello and Lt. Gov. Ralph Northam are squaring off in a fiercely contested primary on Tuesday that will determine the Democratic nominee for governor of Virginia.

Polls close at 7 pm. Vox will be providing live updates on this page about the results of the race, which is expected to be called by late Tuesday night.

Most of the recent polling suggests that Perriello — a former Congress member with strong backing from national progressive Democrats — has a small but real lead going into Election Day. As FiveThirtyEight notes, the polling has been all over the map in the race’s home-stretch. Of the seven polls released in the past week, five have put Perriello ahead by as many as 8 points and as few as 2; two other polls in May, however, gave Northam double-digit margins heading into Election Day.

Still, there’s considerable evidence for a Perriello surge. Despite the support of the state party’s establishment and elected leaders, Northam began the race ahead of Perriello and has since steadily fallen behind. Perriello is seeing huge leads particularly among young voters, who support his candidacy by a nearly 20-point margin. The good news for Northam is that if they fail to show up, the race could swing his way.

A less noticed Republican race

Democrats in Virginia aren’t the only ones holding their gubernatorial primary on Tuesday. Former Republican National Committee Chair Ed Gillespie is the heavy favorite to win the party’s primary, with polling suggesting he has the support of 38 percent of voters.

Nobody else on the Republican side has really cracked 15 percent. Prince William Board of County Supervisors Chair Corey A. Stewart is polling at 11 percent, and state Sen. Frank W. Wagner is at 10 percent, according to the Washington Post. In 2014, Gillespie ran against Sen. Mark Warner and narrowly lost; he’s expected to face far worse odds in a year where the Democratic base appears fired up over President Donald Trump.

The likelihood of a Democratic win in the state is what has fixated all eyes in the political world on the Perriello-Northam race — one the New Republic calls "the biggest Democratic title bout since Hillary vs. Bernie."

A win for Perriello could have national consequences. Months before his opponent even entered the race, Northam sewed up everything that usually decides intra-left state primaries — the endorsements of all of Virginia’s major Democratic officials, backing from the state’s biggest donors, the support of its most powerful interest groups. If Perriello wins anyway, it could send a powerful warning to state Democratic parties everywhere.

"The Democratic establishment in Virginia was not prepared to turn around and fully embrace this populist energy on the left that exploded after Trump’s election," said Quentin Kidd, a political scientist at Christopher Newport University in Virginia, in an interview. "A Perriello win could send a strong message to Democratic establishments across the country: ‘You need to figure out how to deal with this massive new progressive energy before it goes right around you.’"