Their styles could not be more different.

Mayor Allison Silberberg’s eyes light up at the sight of a constituent coming to the Alexandria City Council with a problem, complaint or idea. She listens intently, her body language implying that she has all the time in the world, and finds a way to agree with nearly everyone. She speaks slowly, sometimes in fragments, usually including one of her catchphrases — “livable neighborhood,” “thoughtful, appropriate development,” “our beloved city.”

Vice Mayor Justin Wilson is all energy, multitasking from the council dais while listening to residents then quickly jumping to the implications of what they are saying. He has statistics and trends at the tip of his tongue, and a city-provided iPhone at his fingertips, from which he fires out texts, tweets and Facebook posts nearly nonstop. He favors phrases such as “budget priorities,” “deferred infrastructure spending” and “investment in the future.”

Their Democratic primary battle — essentially the election in deep-blue Alexandria — could be seen as a referendum on how city hall should operate in 21st-century, small-city America, where growth is both a threat to a cherished way of life and a necessary economic engine for local governments perpetually short of cash.

“What’s distinctive about this race is how fundamentally different these candidates are on key local issues,” said Mark Rozell, dean of the Schar School of Policy and Government of George Mason University. “It’s quite remarkable because usually there is a wave of consensus about development. . . . These two hold quite different views, and this is happening in the same political party.”

He and other longtime watchers of Northern Virginia politics expect a close vote in the June 12 primary election. While the 150,000-resident city is increasingly young and racially diverse, political power resides among both the wealthy Old Town retirees who are Silberberg’s strongest base of support and the hyper-organized, working parents in Del Ray, where Wilson’s campaign signs are ubiquitous.

Silberberg, a 55-year-old freelance writer, first attracted local notice when she argued that the city’s waterfront plan would bring too many hotels and too much commerce to the historic riverfront. She has remained skeptical of developers, voting against multiple projects, often ending up on the losing side of 6-to-1 decisions.

She was elected mayor in 2015 after a single term on the council, eking out a victory over incumbent Bill Euille and former mayor Kerry Donley in a three-way Democratic primary, and then crushing Euille’s lackluster write-in general election campaign.

Her first year as mayor was rough, stemming in part from her inexperience with the mechanics of legislating. An attempt to pass a tough ethics policy was hijacked by Wilson and other council members, who stripped it of its teeth. She lost control of a difficult discussion that pitted replacement of a worn public housing complex against historic preservationists and neighbors who sought open space. Council members fed up with ever-lengthening public meetings passed a rule to limit Silberberg’s favorite part — the “open mic” period when anyone can talk for three minutes on any topic.

That change, too, was engineered by Wilson, who calculated that the time spent on public comments had expanded from 30 to 60, on average, and twice dragged on for more than 200 minutes. Silberberg called the cutback “draconian, arbitrary . . . anti-democratic.” He retorted that addressing the needs of all residents, including those waiting for the scheduled agenda items, “is the definition of democracy.”

The argument isn’t over. Last week, Silberberg said that if she’s reelected she will try to reinstate the more open-ended comment option.

Wilson, 39, is a three-term council member whose brash, quick-witted attitude can annoy Alexandria residents who tend to regard public servants as, well, servants.

A detail-oriented senior director of vendor and contract management for Amtrak, he sends out a highly specific email newsletter to more than 8,000 constituents each month, updating them on topics that include sewer and street repairs, early-childhood education and investments in the local economy.

Wilson sees federal budget cuts as “a mortal threat to our future” and has pushed for an emergency local plan to improve the business climate, whether Amazon locates its HQ2 nearby. “Alexandria cannot attract 21st century employers if we have 18th century infrastructure,” he told 120 people at a mayoral debate.

He proposed two recent tax hikes, persuading his council colleagues to boost property tax rates by 5.7 cents in 2017 and two cents in 2016 despite Silberberg’s objections (Alexandria’s mayor does not have veto power). The city’s 1.9 percent revenue growth, he said, simply did not provide enough operating funds at a time when the schools are bulging at the seams, adding hundreds of new students per year, and commercial businesses seem stagnant.

When he mused at a debate last week that the city should improve its long-term fiscal planning by adopting a multiyear budget, as the state does, Silberberg fired back. “That’s what the Soviet Union did, and that didn’t work out so well,” she said, drawing gasps from the business-oriented audience and ridicule on social media.

Wilson does not hesitate to publicly criticize Silberberg, either. He’s repeatedly pointed out that the mayor is inaccurately trying to take credit for decisions she actively opposed or tried to delay — such as a plan to construct two new schools in a single year, or the rejection of a controversial Old Town Business Improvement District.

David Speck, a former council member who has contributed to Wilson’s campaign, said Alexandria needs a leader with Wilson’s deep knowledge of budget and revenue issues, and the nuts and bolts of how local government works.

“Being the dissenting vote in all those 6-1 votes is not an act of leadership,” Speck said. “If you believe strongly in something, bring people along with you. What’s important is, how do you reach a decision beyond appeasing the group that’s [in front of you] at the moment.”

But her supporters are fervent, asserting that Silberberg is the rare elected official who is willing to change her mind based on what the community wants.

Retiree Katy Cannaday, a longtime Democrat who calls Alexandria’s development “very out of control,” sees Silberberg as a thoughtful, concerned listener, and the very essence of what a mayor should be.

“Half the voting population has met Allison. . . . She likes doing this stuff,” Cannaday said. “It’s plain that [Wilson] regards citizen testimony as a formality he has to live through. Allison in contrast, takes notes and responds to specific statements.”

Wilson outraised Silberberg $97,663 to $70,763 through the first quarter of this year, but Silberberg’s campaign manager said they are making up ground and will have the higher overall total by June 4, the last pre-election deadline.

Eight days later, on June 12, voters will have “a referendum on which vision they want to follow,” said Rozell of George Mason University.

“Mango” Mike Anderson, chief executive of the Home Grown Restaurant Group, knows both Silberberg and Wilson and has contributed to Wilson’s campaign. He compares their personalities to those of the employees who work in his restaurants, which include Pork Barrel BBQ, Holy Cow and Sweet Fire Donna’s in Alexandria.

“There are some staff members who connect with customers on a personal level, and [the customers] just love them,” Anderson said. “But do they do a good job of getting the food out of the kitchen in a busy restaurant? Eh, not so much. It’s a trade-off. . . . I think we need somebody who gets that and sees the challenges ahead.”

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