His colleagues on the Arlington County board made Michael E. Brunner chairman for the day at their meeting Saturday.

It was a sentimental gesture, reminiscent of the old TV game show during which a contestant was made "Queen for a Day."

As the only Republican on the Democratic-controlled board for the past four years, Brunner, 44, never stood a chance of being elected to the visible chairman's post for a genuine term.

Though the tenure was brief, the Democrats' tribute was sincere: "We have great esteem for him as an individual and as a colleague," said board Chairman Albert C. Eisenberg.

Brunner's term expires next month, and he did not run for reelection this fall, citing the obligations of his job as chief executive of the National Telephone Cooperative Association and the wish to spend more time with his family. His wife Elizabeth is a psychologist for the Arlington schools. They have two teen-age sons.

Lawyer William G. Newman won election to replace Brunner and will give the Democrats complete control of the five-member board next year.

Brunner's departure comes as Arlington Republicans face some tough questions about the party's future.

The party boasted of a resurgence and backed seven candidates, including two for the county board, in the Nov. 3 election. None of them won. In the county board and sheriff's races, the Republicans lost by greater margins than they did four years ago.

"We had without a doubt the most active election year operation ever," said Arlington Republican Chairman Scott McGeary. But "you don't rebuild a party overnight."

Others are more blunt.

"The Democrats know more identified Republicans than we do," said Bill Miller, a party activist. He was alluding to the Democrats' extensive grass roots precinct operations.

Richard A. Staley, an ally of McGeary's who is expected to become first vice chairman of the party, said there is "deadwood" in the party's leadership. Some party members appear only at the election night party, he said. By the time campaign workers arrive, "the food is gone, the bar is dry."

As Brunner's term comes to a close, his fellow Republicans give him mixed reviews. Part of the ambivalence comes from his popularity with his colleagues. After all, they figure, if the Democrats like him so much, how good a Republican is he?

"I think he has done as good a job as he could considering the last couple of years he couldn't even get a second on a motion," said Staley. "When you're one out of five, you can't do much more than hold the flag. He has."

There are some hard feelings about Brunner stemming from the 1983 election. Some believed that Brunner's campaign organization had not done enough to help fellow Republican Walter L. Frankland, who was running for reelection to the board.

"He was my running mate, but I use that in quotes," said Frankland in an interview last week. He said that Brunner, who has a low-key style and rarely spoke during board meetings, "could have been a little more visible or vocal" on some issues.

But Frankland tempered his criticism by saying that Brunner was able to appoint some Republicans to county panels. "He did the best he could under the circumstances."

Brunner describes his term as successful, saying he has been effective and has kept his campaign promise to be open-minded.

"I think I have been someone who listens," he said. "I have often gone to a board meeting without having made up my mind how to vote on an issue and have been persuaded by the debate, argument and citizen testimony."

Elected in 1983 as a Republican-backed independent, Brunner was seen as a moderate and drew support from Democrats as well as Republicans.

Early on, he voted in the minority against a resolution calling for a bilateral nuclear freeze, saying it was a national issue, not a county issue. He opposed a county affirmative action plan, saying its goals and timetables could lead to quotas.

He voted against three of the past four county budgets, criticizing the growth of the bureaucracy and arguing for deeper tax cuts. He voted for the budget this year, saying the spending rate was acceptable.

Brunner's fiscal caution has extended to voting against new state-of-the-art garbage carts for residents, calling them an unnecessary expense. This year he voted against a new pay plan for county employes, saying costs were not spelled out.

"I come from a basis of wanting to spend less rather than more," said Brunner. "I have not often prevailed, but I expressed a point of view that hadn't been expressed."

On another issue, Brunner approved county backing of an agreement that will set aside 200 units of the Lee Gardens apartment complex for low-income tenants. Lee Gardens "sent the message that Arlington County is serious about maintaining diversity," he said.

Kenneth J. Ingram, a Republican moderate who has been active in local politics, said Brunner's greatest impact has been through his personality. While previous Republican board members have been confrontational, Brunner "has been upbeat even when taking a dissenting point of view."

"It's created a positive image for Republicans . . . and been healthy for Arlington," said Ingram.