Arlington County Board member John Vihstadt talks with a voter after a debate in October. (Patricia Sullivan/The Washington Post)

As Arlington County Board member John Vihstadt worked the polling places on Election Day, he had an inkling that this was not the same electorate that swept him into office four years ago and voted for him again just months later.

“So many voters would say things to me like, ‘Who are you?’ ‘What are you running for?’ One thought I was on the School Board. Another even thought I was the local congressman,” Vihstadt said Wednesday.

In the end, after months of campaigning and 4½ years of governing, Vihstadt’s immediate political future drowned in a blue wave that swept through his deeply Democratic community.

Vihstadt, a political independent who for years was active in Republican circles, lost to Democrat and first-time candidate Matt de Ferranti (D) by about 7,000 votes, according to unofficial returns, a margin of about 7 percent. Their race was just about the only competitive one on the local ballot.

“I think this was a microcosm of the crosscurrents that are sweeping this nation,” Vihstadt said. “It was blue, straight-ticket partisan voting that was deliberately calculated to ignore local issues and candidates.”

Vihstadt stunned Democrats four years ago when he won a low-turnout special election on the strength of his criticisms of high-cost construction projects that the county was planning.

Democrat Matt de Ferranti and John Vihstadt prepare to debate at a candidates forum. (Patricia Sullivan/The Washington Post)

He was the first non-Democrat elected in Arlington in 15 years, and he repeated the feat to win a four-year term that fall.

But this year, when more than 70 percent of active voters turned out in Arlington, breaking all county records for turnout in a nonpresidential election, Vihstadt could not survive. (Virginia voters do not register by party.)

In interviews outside polling places on Tuesday, several residents said they were intent on sending a message to Washington and had little interest in local matters.

Some shrugged at questions about local races and said that without knowing the issues or candidates, they chose only Democrats.

A partner in a Washington law firm, Vihstadt is not shy on the dais about questioning those who are spending Arlington taxpayers’ money.

Shortly after he was elected to a full term, his board colleagues joined with him to cancel the expensive Columbia Pike streetcar project, which he had tirelessly campaigned against. Vihstadt also pushed through legislation to hire an independent auditor, whose job is to examine county books and report directly to elected officials.

As a candidate, Vihstadt adopted a campaign color of purple — a combination of Democratic blue and Republican red. He supported expanding affordable housing, school construction and improving parks and transit, all positions that fit neatly into heavily Democratic Arlington’s self-image.

Running as an independent helped him in 2014, and with at least some voters this year.

“I’ve been following him a little bit, and he has come up with good ideas,” said Anne Lewis, 68, who is retired from the Metropolitan Washington Airports Authority.

“I think he’s done a very good job, and I think it’s important to not just have an echo chamber” on the board, said Raitis Grinbergs, 46, a software engineer.

Jim Presswood, the county GOP chairman, said it’s tough to convince a transient electorate that is not engaged in local issues.

“A lot of people here look only at national politics. If you just heard from the folks who lived here a long time, [Vihstadt] would have won quite handily,” Presswood said. “I don’t mean to say we don’t want [the newcomers]. But if there’s anyone who’s done a better job in Arlington, I’d like to meet him.”

Vihstadt is not a supporter of President Trump, he told those who asked. He voted for Ohio Gov. John Kasich in the 2016 Republican primary and endorsed Sen. Tim Kaine (D) for reelection this year over GOP nominee Corey Stewart, whose anti-immigrant and right-wing tactics alienated many Virginians.

He did not win all his chal­lenges, but he could ask enough hard questions to effectively delay some projects until the county manager’s office provided more information.

On Wednesday, County Board Chair Katie Cristol (D) praised Vihstadt’s personal touch and ability to draw in residents who felt they were not being heard. His fiscal skepticism taught the county a lesson it won’t soon forget, de Ferranti said.

Jill Caiazzo, the local Democratic Party chair, thanked Vihstadt for his service in an election night statement, adding: “Today, a decent person lost, and a decent person also won — the fact that both statements can still be true in Arlington should give us all hope for the future of our democracy.”

Vihstadt said that supporters have already begun asking him to run again next year but that he’s not yet ready to make a decision. He warned, however, about an all-Democratic board resuming control in January, as Arlington is facing major budget gaps, slow growth and persistent requests for more services.

“There’s a severe danger of backsliding by the 100 percent one-party government,” Vihstadt said. “A year from now, people will be asking who is managing the store.”