Christian Dorsey, Candidate for Arlington County Board. (Courtesy of Christian Dorsey)

Kate A. Cristol and Christian E. Dorsey won the Democratic nominations Tuesday for two open seats on the Arlington County Board, paving a way for a new governing coalition in what was a close election between six candidates.

Cristol had 23 percent of the vote, according to unofficial results, and Dorsey had 22 percent. Peter Fallon had 20 percent.

Cristol, 30, an education policy analyst, campaigned on the needs of young adults, young families and immigrants in the county. Dorsey, 43, an executive with the Economic Policy Institute, promised to implement more restraints on county spending.

Cristol said she ran on a message of unity, after controversies over the sale of a farm house and the defeat of a streetcar project along Columbia Pike.

“Folks are ready to move past division,” she said, adding that she plans to work on affordable housing and furthering economic development along the pike. “I want to make sure that Arlington remains the diverse and economically competitive environment that we all value so much.”

Katie Cristol, Candidate for Arlington County Board. (Photo by Emily Goodstein)

Dorsey said his and Cristol’s victory showed that voters worry about the needs of lower-income families in a county where housing costs are continually rising in some neighborhoods.

“If you look at the two of us together, the message that becomes clear is Arlington voters really responded to our message to expand affordable housing for people at all income levels and to ensure our schools maintain the high quality that makes Arlington a choice place for not only residents but also businesses,” he said.

In liberal-leaning Arlington, the Democrats will be heavily favored to win the general election in November. They will be running to replace longtime members Mary H. Hynes (D) and J. Walter Tejada (D), both of whom will retire at the end of the year.

It’s the first time in 30 years that two seats are open on the five-member board.

At least two independents, former Green Party candidate Audrey Clement and former Republican candidate Michael McMenamin, have already announced they will oppose the Democratic nominees in November.

All six Democrats who competed in the primary described themselves as progressives. But all also promised more scrutiny on spending, an unusual theme for Democrats in this wealthy Northern Virginia suburb.

Mindful of last year’s election of John Vihstadt (I), the first non-Democrat to win a seat on the board in 15 years, the candidates all pledged allegiance to fiscal responsibility.

The Democrats also said they were concerned about a growing vacancy rate in office buildings, spurred by cuts in federal jobs.

All denounced the County Board’s sudden decision in May to put the historic Reeves farmhouse up for sale.

The other candidates competing were Andrew Schneider, James Lander and Bruce Wiljanen.