Alexandria Mayor William D. Euille. (Patricia Sullivan/The Washington Post)

NORTHERN VIRGINIA Democrats are holding local primary races June 9 for Alexandria mayor and the Fairfax and Arlington county boards. These are The Post’s endorsements in those races. (Endorsements in Democratic primaries for state legislative races in Northern Virginia will appear separately. There are no local Republican primaries.)

Alexandria

In the heavily Democratic city, Mayor William D. Euille faces his first primary challenge since he assumed his current office in 2003. His opponents are Kerry Donley, who preceded him as mayor and now wants the job back, and the current vice mayor, Allison Silberberg.

Mr. Euille, well liked even by opponents for his decency and civil demeanor, is sometimes criticized as tending more to ceremony and process than to policy. Mr. Donley, in particular, has suggested that the mayor has dragged his feet on major projects. In fact, Mr. Euille has been a good mayor; he deserves reelection to a fifth three-year term.

Mr. Donley, who is respected by his former council colleagues, attacks the mayor for allowing the percentage of city spending devoted to education to slip. Yet he cannot say whose ox he would gore to divert more funds to schools.

No doubt, Mr. Donley is the more forceful personality. He is probably right that he would shake things up. Yet to what end? Mr. Euille, in his soothing way, was instrumental in shepherding a redevelopment plan for Alexandria’s waterfront, which had been debated for decades, and he struck a deal to build more affordable housing around Potomac Yard. In a city of 150,000 people facing serious challenges — crowded schools, sluggish revenue growth, aging and inadequate infrastructure — the mayor has been effective.

As for Ms. Silberberg, she is not a credible candidate. Elected to the city council less than three years ago, she is known mainly for sniping at controversial development proposals, thereby playing to the galleries, but without advancing or articulating viable alternatives.

Arlington County

Six candidates are vying for two empty seats on the five-member County Board. The best are Kate A. “Katie” Cristol, a highly talented newcomer who has impressed community groups with her drive and intelligence, and Peter C. Fallon, whose command of policy derives from a decade of experience on the county planning commission and a wide array of participation in other civic groups. Both are serious and substantive.

Fairfax County

Democratic primaries will choose the nominee in two of the county’s nine supervisor districts: Mount Vernon and Mason.

In the four-way race in Mount Vernon District, the best of the candidates is Timothy J. Sargeant, who is serving his third four-year term on the county planning commission. None of his rivals on the ballot comes close to matching his breadth of knowledge on issues ranging from housing and transportation to development.

In Mason District, the incumbent, Penelope A. Gross, seeks a sixth four-year term. She faces nominal opposition from a neighborhood activist, Jessica Swanson. Ms. Swanson has tried to make hay of crowding and traffic in the area, which includes Annandale and Seven Corners, but her attacks on Ms. Gross, who has a record of deep commitment to the community, are unconvincing.