Republican Bob Harrington is challenging incumbent Ellen Bozman for a seat on the Arlington County Board. But for Bozman, an Independent with Democratic backing, the issue in next Tuesday's election is not Harrington, but the board's sitting Republican majority.

In her literature and on the campaign trail, Bozman has accused the Republicans of "backroom" tactics in the firing last August of former county manager Vernon Ford, of bypassing public participation last winter in the selection of a school board member, and of threatening Arlington's tradition of open government.

"Keep the Door Open," goes one Bozman appeal. In another, she warns of an "uncertain future" for Arlington schools under Republican policies that she says have placed quality schools "in jeopardy."

Those are strong words for a two-term incumbent generally favored to win reelection at the polls next Tuesday. But Bozman, 56, herself a product of Arlington's network of civic activists, is a fervent believer in the so-called "good government" tenets that once held sway over Arlington politics.

On these issues, particularly on education, Bozman this year senses "a clear division" between herself and her fellow Democratic County Board member John Milliken and their three Republican colleagues. And Harrington, 63, by lining up solidly behind the board Republicans, has put himself in Bozman's line of fire.

Harrington has sought to identify Bozman with an era in Arlington government when the liberal Arlingtonians for a Better County -- the ABC faction -- controlled the County Board. Speaking at a civic association last week, Harrington asked: "Are we going to hold the line on taxes or . . . do we go back to the days of the ABC Democrats with excessive spending and skyrocketing taxes?"

A partisan drift in election rhetoric is nothing new in Arlington but this fall, feelings between Republicans and Democrats on the board have been exacerbated by a series of well-publicized events -- most notably the Republicans' decision to keep Democrats in the dark about Ford's firing.

According to Bozman, voters have responded favorably to her attack on the majority's decision to withhold news of the firing until four days after the deed was done. "One lady came up to me at church and said, 'We elected you people to work together,' " Bozman said. "The idea that the three Republicans would not inform us is offensive to a lot of people."

Harrington staunchly defends the decision to fire Ford and has charged that in 1977, Bozman delayed telling her Republican colleagues that she was illegally holding two positions - her board seat and a position on the County Commission on Health -- a situation that caused her temporary resignation from the board. "It is clear," said Harrington, "that Ellen Bozman has double standards."

As the appointed chairman of the Arlington Civil Service Commission (a post he resigned when he decided to run for office), Harrington says he learned firsthand the functions of county government. "I think under Mr. Ford, the county system was fairly well regimented. County employes couldn't speak their piece," he said. More importantly, Harrington -- like his Republican colleagues -- believed Ford failed to keep an eye out for possible savings to the taxpayers.

Harrington, who retired in June as business manager of St. Agnes Episcopal Girls School, shares the Republican view that the main issue in county government is taxes. To civic groups, Harrington proudly points to the successive decreases in the tax rate adopted since the Republican majority took control.

"Mrs. Bozman has voted for every tax increase ever proposed by the Democrats," Harrington said. "She's always voted for more spending, more programs and has always had very little concern for who's going to pay."

Bozman, however, notes that the drop in the tax rate was made possible by increases in revenue from other sources -- including the gasoline tax dedicated to Metro funding, new construction and higher real estate assessments. Arlington's tax burden, she is quick to note, was the lowest of any Washington metropolitan jurisdiction under the Democrats, just as it is today under Republicans.

For all the sparring between the two parties, this year's election will not affect the GOP's control of the board, which is perhaps why some Democrats detect a lack of intensity in the Republican effort. The true test comes in 1982 and 1983 when first GOP Board Chairman Stephen Detwiler, then Republican members Walter Frankland and Dorothy Grotos stand for reelection.

Like all incumbents, Bozman is running on her record - a record that, as her colleague Milliken describes it, is associated with neighborhood issues, "making life in Arlington more workable." Bozman urges a cautious approach to new development, which she says should be kept at a "human scale" and a continuing commitment to preserve moderate-income rental housing.

True to her ABC background, Bozman repeatedly zeroes in on the need to keep open every possible channel linking county government and the involved citizen. "Right now, we are no longer pursuing citizen participation with the same desire. That has always been one of Arlington's real strengths," she said.