Libby Garvey (D), chair of the Arlington County Board, greets voter Laurie Siegel, right, while canvassing for reelection. She faces challenger Erik Gutshall in the June 14 Democratic primary. (Astrid Riecken/For The Washington Post)

The next address on Libby Garvey’s list was marked “SR” — strong Republican — but the Democratic politician who chairs the Arlington County Board didn’t hesitate. She told the homeowners she is running for another term, has the support of a well-known Republican colleague — and is facing a primary challenger because of it.

The next day, that opponent, Erik Gutshall, wielded his own clipboard as he campaigned in a different neighborhood, pledging to “get in front of rising school enrollment, invest in transportation infrastructure and improve middle-income housing” if he is elected. Compared with Garvey, he said, “I think I can do a much better job of planning for the future.”

Arlington’s June 14 primary pits an admittedly wonky, progressive candidate against a political veteran who has infuriated her party by shunning the liberal stances that are a hallmark of this diverse, wealthy, inside-the-Beltway community.

It is another political Rorschach test for the deep-blue Arlington electorate, which over the past two years has wavered between a fiscally conservative candidate who questions the status quo and candidates who put more faith in the community’s long-established methods of coming to agreement on government spending.

Arlington County Board candidate Erik Gutshall talks with Karen Serfis in the Ashton Heights neighborhood. Gutshall is a Democrat trying to unseat fellow Democrat and incumbent board member Libby Garvey in the June 14 primary. (Katherine Frey/The Washington Post)

After the 2014 election of Republican-turned-independent John Vihstadt, who was supported by and has now endorsed Garvey, county voters last year chose two liberal Democrats, Katie Cristol and Christian Dorsey, to fill open board seats.

Gutshall, 46, takes that as a sign that Arlingtonians still support progressive politics.

The owner of a home-improvement business who has served on the county’s planning and transportation boards, Gutshall is basing his campaign on a call for making strategic, long-term investments in housing, transportation, schools and parks.

He said he wants to find ways to increase the supply of medium-density housing for those who are being priced out of Arlington but don’t qualify for subsidized programs. Garvey, he notes, has tried to cut the county’s spending on low-interest, long-term loans to organizations that build affordable housing.

Karen Serfis, who met Gutshall as he went door-to-door last week, works for a nonprofit housing agency and said she was impressed by Gutshall’s knowledge of the field. She dismissed Garvey’s emphasis on allowing more “accessory dwelling units” — essentially in-law suites that could be used by non-related renters in existing homes.

“That’s such a small percentage of people that would work for,” Serfis said.

Gutshall’s support for multi-modal transportation won him the vote of Tom Underwood, a retired Foreign Service officer who used to be a bike commuter and who was visited by the Democratic challenger in the Ashton Heights neighborhood.

“We need more public investment in the transportation infrastructure,” Underwood said. “I’ve lived in Europe and Asia, and they’re way ahead of us.”

Others in the neighborhood were less welcoming. Elizabeth Reed lit into Gutshall over rising home assessments, traffic-calming features that she said will force school buses over a curb on her block, and what she described as the impossibility of bicycle commuting “when you work 27 miles away.”

The candidate’s smile froze. He could find few grounds for agreement with her.

Gutshall is hammering Garvey on the issue of school overcrowding, noting her 15 years on the Arlington School Board, including five as chair, before joining the County Board. He also looks skeptically at Garvey’s calls for “flexibility” in the county’s carefully crafted zoning rules.

“I think she has to take some responsibility,” he said. “We’re in the sixth year of discussing [school overcrowding]. I don’t think that’s responsible leadership.”

The challenger says Garvey has been a polarizing presence on the County Board and bears significant responsibility for the declining trust in local government. His supporters note that in addition to backing Vihstadt over the Democratic nominee in 2014, she has accepted campaign donations from Republicans, including $1,000 from former congressman Thomas M. Davis.

Garvey said that she and Davis have worked together on regional matters, particularly transportation. “I’m looking for support from everybody,” she said.

Garvey, 65, is masterful at establishing ties with potential voters. In short order while campaigning last week, she shared the story of her daughter’s long-ago heart surgery with a mom whose son would soon face a similar operation, and bonded with the wife of a cancer patient by talking about her own battle with breast cancer in 2010.

Garvey also suggested that each woman consider voting early, so that pressing medical appointments do not interfere with their civic duty.

An Arlington resident for almost 40 years, Garvey and her late husband arrived in the county after working in the Peace Corps in the Central African Republic. She settled in Fairlington and became active in school issues, advocating for a new elementary school in south Arlington, what is now Carlin Springs.

After a loss on her first try, she won election to the school board in 1996 and lost two primary races for seats in the General Assembly in 2005 and 2011. She was elected to the County Board in 2012.

Garvey says she offers experience in both schools and county issues, connections to leaders around the region and the commonwealth, and fiscal accountability.

“If you like the schools here, I did that,” she tells voters on the campaign trail, adding that the county and the schools are working together to address overcrowding.

Jane Andelman, a 45-year-old mother of two, is concerned about school capacity and was intrigued enough after meeting Garvey to do some research online. What she found, she said, troubled her.

“Washington-Lee High School is already overcrowded after they just completed a new building. That’s disheartening,” she said. “It did make me think twice, with her having been on the school board and not planning appropriately. What was going on before I was paying attention?”

A neighbor down the street, Darrell Capwell, knew of Garvey through his own involvement with the Democratic Party and said he was impressed by her attention to local issues. He offered unambiguous support, saying Garvey “personifies what a good public servant should be.”

As for school overcrowding, “It snuck up on all of us,” Capwell said. “You can’t blame someone for not being able to predict the future.”

The Garvey-Gutshall race is the only one on the June 14 ballot in Arlington. Voter registrar Linda Lindberg said she expects turnout to be in the 8 to 10 percent range, or 10,000 to 12,000 voters. The last day for absentee voting is June 11.