Voters in Arlington County enjoy unusually frequent opportunities to reshape or preserve the makeup of their local government -- with an election each November for at least one seat on the five-member county board. This year, incumbent Ellen M. Bozman is seeking reelection for a fourth term. She is challenged by Richard J. Herbst. Mrs. Bozman's unflagging devotion to local service and her understanding of complex county issues have made her a valuable leader. There are no signs that her vigor has diminished, either. Arlington would be well served by her reelection.

Each candidate is running as an independent, though the partisan affiliations are not at all disguised. Mrs. Bozman has endorsements of the county's Democratic Party and the Arlingtonians for a Better County political coalition. Mr. Herbst has the backing of the local Republican Party but is a federal employee barred by the Hatch Act from running as a partisan candidate.

Mr. Herbst is putting on a constructive campaign. Though he is running for elective office for the first time, he does have years of experience as a community leader in South Arlington. His interest in environmental law has made him a figure in neighborhood battles over freeway paths and site selections for various county facilities.

Mrs. Bozman has been emphasizing the importance of additional county services to keep up with increased public demands. She has been articulate in making distinctions between uncontrolled growth and beneficial developments in the Metro corridors. Add to this a keen sense of local, regional and state governmental relationships, based on service with the Metropolitan Washington Council of Governments, transportation organizations and Northern Virginia planning groups.

By returning Mrs. Bozman to office, Arlingtonians can retain a legislator whose effectiveness extends well beyond the county's boundaries.