Virginia Gov. John N. Dalton yesterday strongly endorsed the State Highway Commission's route for the proposed Springfield Bypass, offering no room for compromise with the Fairfax Board of Supervisors over the highway, which has become an issue in the governor's race.

The Republican governor's emphatic statement, presented to the board at a public hearing on the bypass last night, presented Democratic supervisors with a quickly seized opportunity to criticize the Republican governor, his highway commission appointees and his party's candidate for governor in next Tuesday's election, Attorney General J. Marshall Coleman.

Republican supervisors tried to contain what they acknowledged would be political damage to their candidate by asserting that the public hearing that prompted Dalton's statement was politically motivated.

"I don't agree with the governor," said John F. Herrity, the Republican chairman of the Fairfax board. "But the reason we're having this public hearing today, a week before the election, on one of the hottest issues in the election, is because the Democratic candidate for governor Charles S. Robb called some supervisors and told them to have a public hearing."

Democrats denied that the public hearing, which attracted more than 50 speakers and more than 100 listeners, was political.

"I don't know what the Republicans are complaining about," said Mike Hershman, a Democratic candidate for delegate in Fairfax's 51st District. "The wound was opened because of the misconduct of one of their appointees to the highway department."

Dalton last month pressured Northern Virginia's highway commissioner William B. Wrench to resign when it was was disclosed that Wrench voted for a bypass route that passes near three parcels of property he owns. Candidate Coleman found himself in the embarrassing position of investigating a campaign contributor: Wrench had given him $1,100 and served on his campaign finance committee.

The route Wrench favored for the 35-mile, $200 million cross-county highway differed from the county-preferred alignment over about 10 miles, and county officials were furious. They have tried without success since the commission's August vote to persuade, cajole or force the commission to change its route.

Last night's public hearing, a prelude to placing the county route on the Fairfax comprehensive plan, is the latest such attempt. Some supervisors believe the federal government will not pay for the bypass if the state is pushing a different route.

Dalton's letter, read into the record by a state highway official who drove from Richmond for the hearing, indicated he would not be swayed. "As a result of the unfortunate controversy and erroneous statements which have surfaced, I have examined the route decision of the Virginia Department of Highways and Transportation Commission and I believe the decision to be sound and correct," Dalton wrote.

Some citizens at the public hearing showed no interest in the politics and said they did not want the road built at all. Others, like the president of the county Chamber of Commerce, said their chief concern was that the road get built somewhere. "We must assume, until there is evidence to the contrary, that the (state highway) Commission has acted in good faith," said chamber president Philip M. Reilly.