Rep. Dave Brat (R-Va.) shakes hands with Democratic challenger Abigail Spanberger after a debate at Germanna Community College in Culpeper, Va., on Oct. 15. (Steve Helber/Associated Press)

The headline numbers in the most recent Wason Center poll confirm what we learned a month ago: Virginia’s 7th Congressional District race between incumbent Rep. Dave Brat (R) and Democratic nominee Abigail Spanberger is a pure toss-up.

But inside the numbers are a few nuggets that help us identify trends, ongoing challenges and an X factor.

The most important trend: Brat’s overall numbers still don’t push beyond 50 percent. Traditionally, when an incumbent polls less than 50 percent, particularly at this very late stage a race, that incumbent is in real trouble.

A challenge, for Brat: voter enthusiasm. The Wason poll shows a 16 percentage point “enthusiasm gap” between Democrats and Republicans. Generally, supporters of the party out of power are more excited to vote. But there’s another story behind this particular data point.

The Wason Center’s Rachel Bitecofer told me Spanberger’s biggest group of motivated voters is “white, college-educated women,” a group Bitecofer says has been in play since the 2016 presidential election.

Spanberger has a 14 percentage point advantage over Brat among women overall.

“That’s not great for Brat,” Bitecofer said. “These women will show up to vote.”

But even with that motivated group of voters, Bitecofer said, the Spanberger campaign still has a lot of work to do in the race’s final days to have a shot at victory.

“To win, Spanberger has to fundamentally transform the electorate in the 7th District,” Bitecofer said.

“No matter what Democrats say or think,” Bitecofer said, “they will need a huge Democratic turnout, on par or better than what Ralph Northam’s campaign got in the 2017 governor’s race.”

In that contest, Northam, a Democrat, lost the 7th to Republican nominee Ed Gillespie. But Northam won the vote-rich suburban counties of Henrico and Chesterfield — the latter being the first by a Democrat running statewide in decades.

Democrats also took from Republicans three House of Delegates seats that overlap the 7th District.

Spanberger will need that kind of turnout because, Bitecofer said, Spanberger’s strength is “entirely suburban,” and a good share of it comes from “casual Democratic women voters” who might otherwise skip a midterm congressional race and new voters who were too young to cast ballots before this year’s elections.

But even if they all show up, Spanberger will still need help. Bitecofer believes she may get it from Libertarian Joe Walton.

Walton polls at 4 percent in the Wason poll – just inside the 4.2 percent overall margin of error.

In a Twitter message to local media, Walton touts the 4 percent figure and notes the line in the center’s press release stating his presence “could make the difference in a tight contest.”

Bitecofer noted that pre-election support for third-party candidates typically falls by half or more when voting gets underway.

Even if that occurs, it would put Walton, conservatively, at 1 percent or 1.5 percent — still a potential difference-maker.

And also just enough to make Walton a spoiler.

While Republicans usually toss that epithet around to excuse their own nominee’s failings, Bitecofer believes the label may be accurate in the 7th District contest.

Walton’s campaign disagrees. In an email, campaign spokesman John Vaught LaBeaume said “many voters are embarrassed by Brat” for his stands on social issues and are “skeptical that Spanberger can stand up to Democratic activists trying to pull her to the far left on the economy.”

And if enough of them pick Walton, he will be “less likely to face a third-party drop-off effect.”

But on the bigger question — will the 7th flip from GOP to Democratic control — Bitecofer remains confident of the conclusion she reached this summer: “The 7th District will flip,” she said.

We will get another polling snapshot of the 7th District race from the New York Times/Siena College this week.