Democrat Abigail Spanberger, left, and Rep. Dave Brat (R). (Carlos Bernate/Bloomberg; Timothy C. Wright for the Washington Post)

A new poll confirms that the race in Virginia’s 7th Congressional District between incumbent Rep. Dave Brat (R) and challenger Abigail Spanberger is a genuine toss-up.

That’s not good news for Brat. The 7th District is drawn to elect a Republican. It got a little less GOP-friendly after court-ordered redistricting redrew the lines in advance of the 2016 congressional elections.

Brat won handily under the new lines in 2016. He may not be as lucky this November.

The numbers from a Monmouth University poll released Tuesday show why.

Under various turnout models, Brat never exceeds 50 percent of the vote. Conventional wisdom says an incumbent polling less than 50 percent is in trouble.

Monmouth’s headline number shows him trailing Spanberger 47 to 42 percent.

Brat’s best-case scenario is what Monmouth calls a “historical midterm model,” which has the race tied at 47 percent.

Monmouth’s model showing a “possible turnout surge in Democratic precincts” puts Spanberger ahead of Brat 48 to 45 percent – essentially a statistical tie.

Monmouth’s data also reinforces points I’ve long made about the race: Spanberger’s strength is in the Richmond suburbs; Brat’s is in the more rural counties.

I asked University of Richmond political science professor Dan Palazzolo about the latest data. He said the Monmouth poll confirms that the race is close. But there were a few items buried in the crosstabs that got his interest.

“The [polling] sample has more women than men (8 percent more), plus a third were “Independents,” Palazzolo said. “This might account for Spanberger’s lead in this poll.”

He pointed out that “the composition of voters would need to look like [the poll’s sample] for Spanberger to win.”

Palazzolo also noted a “puzzle” in the poll: voter attitudes toward President Trump.

“Trump’s approval rating is higher than the national average” in the 7th District poll, “and the party preference [for who should control Congress] is split or leaning GOP.”

“Ironically,” Palazzolo said, “these are two indicators that should favor Brat.”

But they don’t appear to do so in the Monmouth data.

“One might expect a lower approval rating for the president and a lower level of preference for a Republican from a sample that favors Spanberger,” Palazzolo said.

How do we solve such a puzzle? Palazzolo said “the answer may lie in the voters’ evaluation of the two candidates.”

“It is quite interesting to see that not only does Spanberger have a higher favorable rating [than Brat], but just as many respondents have an opinion of a challenger as they do of an incumbent.”

Forty-three percent of voters surveyed had a favorable opinion of Spanbeger. Brat had 35 percent. Thirty-nine percent had no opinion of Spanberger, while 37 percent had no opinion of Brat.

What’s driving Spanberger’s name recognition? Palazzolo said the challenger “has run a very good campaign in terms of raising her personal profile.”

That has added a new winkle to the race’s final weeks.

“Respondents in this poll who favor Spanberger do not appear simply to be ‘voting against Trump’ or in protest,” Palazzolo said. “They are voting for her.”

Palazzolo said that a healthy portion of self-described Republicans not planning to vote for Brat “does not bode well for him.”

Unlike Brat, Spanberger “seems to have managed to consolidate Democratic support and engage independents,” Palazzolo said. Brat is “still working on bringing home all of the Republicans he will need.”

The question is what will motivate them.

I asked Palazzolo whether there might be any political fallout from the Supreme Court confirmation hearings for Judge Brett M. Kavanaugh.

Palazzolo said the Kavanaugh circus in largely tangential in a House race. Because Brat cannot vote on the nomination, any fallout, particularly among women, is “already baked in” to the race’s dynamics.

“Absent the Kavanaugh debacle,” Palazzolo said, “there is already unprecedented support for a Democrat in the 7th District.”

“That’s all due to Spanberger,” he said.