Volunteer researchers answer questions as residents hold a town hall meeting in Sterling, Va., despite the decision of Rep. Barbara Comstock (R-Va.) not to attend. (Amanda Voisard/for the Washington Post)

A single silent microphone awaited a congresswoman who never materialized Friday night as dozens of her constituents vented their frustration at her absence, analyzed her voting record and dissected her campaign promises.

Rep. Barbara Comstock (R-Va.) was 15 miles away, attending the annual Catholic Charities Ball.

Activists from the Indivisible VA District 10 Facebook group hosted the “citizen’s town hall” at the Sterling Community Center and set up the mic in case she decided to join them.

“That woman would show up to an opening of an envelope, so the fact that she would not show up tonight is incredibly insulting to me and to all of us,” said Kona Gallagher, 36, from Ashburn.

A crowd of about 150 applauded but left the pithy signs and heated rhetoric at home.

Residents participate in a town hall meeting in Sterling, Va. (Amanda Voisard/for the Washington Post)

The sedate forum unfolded in the battleground county of Loudoun as voters elsewhere in Virginia — and across the country — planned similar events to seek answers from their elected representatives about the agenda of the GOP-controlled Congress and President Trump.

Some members, like Comstock, have eschewed the public forums out of fear that angry residents will shout them down and create a circuslike atmosphere, as happened Tuesday to Rep. Dave Brat (R-Va.) in Southside Virginia.

In Rep. Bob Goodlatte’s district in southwest Virginia, residents addressed their questions to a cardboard cutout of the Republican at a “People’s Town Hall” on Wednesday night outside Roanoke.

Goodlatte, who is chairman of the Judiciary Committee and traveled to India this past week with House colleagues, prefers to hold town halls via telephone — where thousands can listen in but only a handful get to ask questions.

After repeated calls and emails from constituents, Rep. Thomas Garrett, a freshman who represents central Virginia, announced Friday that he would hold a town hall on March 13. Indivisible Charlottesville and like-minded groups are planning to hold one of their own Garrett town halls Sunday. Two high school students will serve as volunteer moderators.

In Maryland, a chair with a sign that read “reserved for [Rep.] Andy Harris,” a Republican, sat empty Tuesday evening at a meeting about the possible ramifications of the repeal of the Affordable Care Act. Two days later, Harris announced details for a March 31 “brick-and-mortar town hall” at a middle school.

Back in Sterling, the crowd eschewed the cardboard doppelgänger and recruited author and culture critic Todd Kliman to serve as moderator.

Kliman hosted a five-event conversation series in Washington called “WTF Now?!” after the election that featured economists, policy experts, historians and others discussing the Trump presidency.

At times, the event on Comstock’s turf seemed more like a policy seminar than a protest.

“Russia was involved in the 2016 election,” said Sue Reilly, a 67-year-old Ashburn resident. “How are you going to make sure that the issue is investigated independently?”

A volunteer researcher and constituent, Guy Potucek, read from a slide projected on the cinder block wall that listed Comstock’s earlier statements about the subject, as well as her tweets saying that she supports investigations by the House and Senate Intelligence committees.

Asked if that answered her question, Reilly, silently raised a small sign that read “Boo.”

Matthew Zelman, a 35-year-old Centreville resident, teared up as he talked about his 5-year-old son’s friend, a so-called anchor baby who was born in the United States to parents who are undocumented.

“They are about as American as anybody I ever met in my life,” he said. He would ask Comstock, “Do you consider those people to be criminals? They’ve never had a speeding ticket in their lives.”

Thomas M. Davis III, a moderate Republican and former congressman from Northern Virginia, said he understands why members in reliably red districts would avoid contentious confrontations with voters.

But, he said, swing districts like Comstock’s are different.

“You need to talk to everyone,” said Davis, who also represented a swing district. “For me it was survival.”

Comstock has held telephone town halls, which bothers some activists who say the format is overly controlled. That frustration was clear among some of the participants Tuesday night, when Comstock held her second call in recent weeks.

A caller told Comstock she spent “a lot of time talking in circles and not answering the question.”

“People are reasonable,” the caller said, according to a recording. “I don’t think that you would be attacked by disrespectful people or protesters. I think people really just want an open back-and-forth dialogue with people face to face.”

Comstock said she cannot effectively address voters’ concerns at a large town hall, and especially not one featuring Kliman, whom she referred to as “a food critic from Maryland.”

She would rather have small meetings for “back-and-forth dialogue,” she said, and ran through a gantlet of 30 of them Friday at her Capitol Hill office.

“It was very informative to hear specific individuals’ personal stories, concerns and health care situations and it reinforced my conviction that we need to do health care reform in a methodical way that respects these life and death situations,” she said in a statement.

Activists continue to flood Comstock’s office with phone calls and meeting requests. Images of her photo superimposed on milk cartons proliferate online, and a “Where’s Comstock” website attempts to track her movements.

They urge her to release her public schedule in advance, as many elected officials do as a matter of policy; Comstock has declined. Instead, her staff uses social media to share details about her events after they happen.

In Sterling, Mike Turner, a retired Air Force colonel who ran for the Democratic nomination for the seat Comstock now holds in 2008, raised a pocket-size copy of the Constitution — similar to the actions of Khizr Khan, the father of an Army captain killed in Iraq, at the Democratic National Convention last year.

Turner, 65, of Ashburn, said he “never imagined that the chief enemy to this document would be the president of the United States.” The audience stood and clapped.

“When the impeachment comes — and it’s coming … Representative Comstock, will you vote with your constituents, for the people who pay your salary, or not?” he said.

Before the forum, Virginia GOP Chairman John Whitbeck, who is a former head of the party committee in Comstock’s district, called such antics “faux outrage.”

“Just because she won’t have a town hall with a bunch of liberals who despise her doesn’t mean she’s cut off from her constituents,” he said.

The proof is in the election results, he said.

Despite projections from independent analysts that her race would be a nail-biter, Comstock won reelection to a second term in November by six percentage points. Trump lost the district by 10.