This is part of a series on the Aug. 23 General Assembly primary elections in Northern Virginia. The series will appear in August.

Call it the Rorschach Race: Everyone looks at the Democratic primary in Virginia’s 31st Senate District and sees something different.

To one candidate, Arlington County Board member Barbara A. Favola, it’s about “bread-and-butter issues” — transportation, education and the environment. To the other, lawyer Jaime Areizaga-Soto, it’s about who will fight hardest for “Democratic values” against Republicans in Richmond.

And to longtime political observers in Northern Virginia, it’s one of the most heated, unpleasant races in recent memory.

“It’s much more negative than Arlington is used to, and it’s unfortunate that both candidates have gone down this road,” said Del. Patrick A. Hope (D-Arlington), who considered running for the 31st District seat and is staying neutral in the primary. “I wish they would focus on the issues.”

Barbara Favola and Jaime Areizaga-Soto are facing off in the Democratic primary in Virginia’s 31st state Senate district. (Dayna Smith/For The Post)

Just as car accidents draw gawkers, the contest to succeed retiring state Sen. Mary Margaret Whipple (D) has drawn significant attention, even in a year in which several other competitive primaries dot the region.

The redrawn 31st District — which snakes along the Potomac River from Arlington to eastern Loudoun County — still clearly favors Democrats. But as the party looks to keep its 22 to 18 advantage in the Senate, some Democrats worry that a nasty primary will hurt the eventual nominee in the race against Republican candidate Caren Merrick, the wealthy co-founder of a software company.

Del. Robert H. Brink (D-Arlington), who backs Favola, has accused Areizaga-Soto of “Karl Rove-style mudslinging.” But Areizaga-Soto makes no apologies for the campaign he’s run.

“If you look at my mailings, if you look at my Web site, if you look at my work — it’s overwhelmingly positive,” Areizaga-Soto said.

Yet he did allow that it was important to “make some contrasts” with his opponent, and that’s just what he’s done.

‘It’s unusual for Arlington’

To put the brawl in schoolyard terms, Areizaga-Soto started it.

In campaign mailers, he has asserted that Favola’s “vote is up for sale” and that she has violated the Arlington board’s self-imposed ethics policy by taking contributions from developers with business before the county. Areizaga-Soto also criticized Favola for taking $2,500 from a towing company days before voting for a measure to increase towing fees in the county, calling on her to resign from the board.

Favola said she was “appalled” by his allegations. “I mean, there’s no way I ever sold my vote — ever, ever, ever,” she said.

Because some of her donors have also given to Gov. Robert F. McDonnell (R) and Attorney General Ken Cuccinelli II (R), Areizaga-Soto’s mailers have placed Favola’s picture between the two Republicans’ and declared that they have “a lot in common.”

Favola, for her part, commissioned a telephone poll that referred to Areizaga-Soto as a Republican. Her campaign later pulled the poll and blamed the mistake on “a clerical error.”

Areizaga-Soto has worked as an aide to Whipple, but even that position has been a matter of dispute. Areizaga-Soto calls himself a “policy adviser” to the incumbent. But Whipple, who has endorsed Favola, released a letter this week saying that the title — while technically accurate — exaggerated his duties and that he was really just an “intern.”

“Jaime’s embellishments and exaggerations of his role during his time in Richmond have bothered me for some time, and I feel compelled to set the record straight,” Whipple said in the letter.

Former delegate Margaret G. Vanderhye (D-Fairfax) had planned to stay out of the primary. When Areizaga-Soto leveled his initial attacks on Favola, Vanderhye was disgusted enough that she endorsed Favola. Then Favola returned fire, and Vanderhye was so put off that she asked Favola not to use her name publicly anymore.

“We are squandering this opportunity on an unnecessary campaign that is destructive to the party,” Vanderhye said. “We are missing a golden opportunity to get our message out. . . . I’m very disappointed with both of them.”

Not everyone is so bothered by the tone of the campaign.

“It’s unusual for Arlington,” said Richard E. Trodden, the Arlington commonwealth’s attorney, who has endorsed Areizaga-Soto. “But I don’t think these are unfair subject matters to be talking about.”

Divergent profiles

Favola, 56, has lived in Arlington for three decades and has served on the Arlington County Board since 1997. She also works part time in government relations and development for Marymount University.

Areizaga-Soto, 41, is a former official in the U.S. Agency for International Development and serves in the Judge Advocate General Corps of the Army National Guard. He was born and raised in Puerto Rico.

The candidates do agree on one thing: They don’t disagree on much.

Asked what substantive issues divided himself and his opponent, Areizaga-Soto said his “energy and enthusiasm for Democratic values is more apparent,” but he had trouble pinpointing many specific differences.

When he is out knocking on doors — he says he’s lost 12 pounds walking the district — Areizaga-Soto hits repeatedly on the same theme: He is going to Richmond to “fight the McDonnell-Cuccinelli agenda.”

Areizaga-Soto also emphasizes his support of abortion rights and his endorsement by the LGBT (lesbian, gay, bisexual and transgender) Democrats of Virginia’s political action committee. It’s a message he hopes will resonate with grass-roots Democrats, particularly in an Aug. 23 primary that is likely to see low turnout. “I am definitely the more progressive candidate in this race,” he said.

Favola scoffed at that idea, saying that she is just as supportive of abortion rights and gay rights — but with a longer record of advocacy.

“There’s no substantive difference on these social issues,” Favola said. “I don’t know where my opponent stands on the bread-and-butter issues. He doesn’t talk about them.”

A different district

Under the old lines, the district was a relatively compact combination of Arlington and part of Falls Church. Now, the 31st stretches from Arlington all the way to eastern Loudoun County, picking up McLean and Great Falls along the way.

The new district has combined communities that don’t always see eye-to-eye. Many Arlington residents, for example, are opposed to widening Interstate 66 because they fear increased pollution, but commuters further out in the district rely on that busy artery to get home.

Favola said voters ask her different questions, depending on which part of the district she’s visiting. In fast-growing Loudoun County, they’ve been asking her about new schools and class sizes. In a Great Falls debate, she was asked about the progress on extending Metrorail to Dulles Airport.

Everywhere she goes, she is asked about environmental issues, because nearly everyone in the new 31st lives near the Potomac River.

“That’s really the one unifying factor in the district,” Favola said.

Although it still favors Democrats, the new seat is friendlier to Republicans. In his 2009 gubernatorial win, McDonnell took 35 percent of the vote in the old district and would have received 44 percent in the new one.

Some Democrats fear that whichever candidate loses will hold a grudge against the winner and imperil the party’s ability to hold the seat in November. Areizaga-Soto doesn’t buy that, calling the 31st “a safe Democratic district” that could only be lost by a “very weak candidate.”

Merrick, who faces no opposition in the Republican primary, has been quietly letting the Democrats squabble while she builds a campaign war chest. Merrick had $153,000 in the bank as of June 30. Favola had $113,000, and Areizaga-Soto had $41,000.

Despite the bickering, either Democrat is prepared to endorse the other once the primary is over.

“The chips are going to fall where they may,” Favola said. “I’ll be fine the day after, either way.”