Robert F. Horan Jr., commonwealth's attorney for Fairfax County, conducted a provocative workshop the other day on ways to rile the Virginia gentlemen on a Senate committee.

Begin by calling them bureaucrats. Then complain that they are stingy. Finally, upstage them on their own stage.

"This gentleman is going too far," complained a red-faced, Democratic senator from Hampton, Hunter B. Andrews, who is a member of the committee Horan was trying to persuade. "He is making a political speech."

The issue that brought Horan to Richmond and members of the Courts of Justice Committee to anger is a locally financed magistrate system that is unique to Fairfax County. Under that system, 39 full-time and part-time magistrates issue arrest warrants, set bail for criminal defendants and collect traffic fines, at a cost to county taxpayers exceeding $600,000 a year.

The state has its own corps of magistrates who perform the same functions in all local jurisdictions except Fairfax. State officials, and some from Fairfax, argue that the county could get the same services without having to pay the salaries, by letting the Commonwealth absorb the Fairfax magistrates.

"We're trying to correct a somewhat awkward position and create some uniformity," said Robert Baldwin, executive secretary of the Virginia Supreme Court, whose office controls the state magistrate system.

But Fairfax officials who sided with Horan argued that their local magistate system provides better service than they would receive from the state. They also voiced fears that the state would prove a fickle parent and refuse to adopt all of the county magistrates.

"It would be nice to clean up the code" by eliminating the section allowing Fairfax to have its own magistrates, said Terrence O'Brian, the county's legislative liaison in Richmond. "But we have 39 people and they are more important than a tiny code."

Fairfax Sheriff Wayne Huggins told the committee that reducing the number of magistrates would increase the population of his already-overcrowded jail.

Sen. Edward Holland (D-Arlington), who sponsored the bill eliminating Fairfax's separate system, countered that no decision had been made on how many magistrates Fairfax would receive if it were taken into the state system.

Horan, who is noted for his courtroom speeches, then took his turn at a podium facing the semicircle of senators. He argued that Fairfax should be allowed to spend its money as it wished.

"We have good personnel, good service and citizens who don't mind paying," said Horan, who accused the lawmakers of emulating the federal bureaucratic "octopus," enslaving local governments with regulations. "If I thought the federal bureaucrats were the only ones [guilty], I would be a lot more comfortable worshipping at the altar of uniformity."

Sen. Andrews angrily interrupted Horan at that point to accuse him of promoting self-serving interests under a banner of local autonomy.

"Don't mislead the newspapers," said Andrews, his voice rising. "You get the fees that finance this sytem."

Horan denied his office was interested in empire building, but he was interrupted again by Sen. William Parkerson (D-Henrico), chairman of the Courts of Justice Committee. "We're not arguing to a jury or anything," said Parkerson.

"You don't need to use buzz words like 'big, bad bureaucracy' here," added Holland.

The county's magistrate system is not unanimously supported by Fairfax officials. County supervisor Audrey Moore voted last year to join with the state because of the cost of the local magistrate program. But Moore conceded that it was a "delicate issue" because of the "personal feelings" involved.

The most personal issue concerns the chief magistrate in Fairfax, Milton Alexander. He is the father of Joseph Alexander, the senior member of the Fairfax Board of Supervisors. Because magistrate Alexander is 71, one year past the state's mandatory retirement age, a move to join the state would force him to retire.

Supervisor Alexander opposes the state takeover, but he denies his opposition is motivated by his father's $21,000-a-year job. Fearing the state might absorb the Fairfax magistrates, Alexander and his colleagues persuaded Sen. Joseph V. Gartlan (D-Fairfax) to introduce a bill to exempt the elder Alexander and two other current magistrates from state requirements. The provisions of that bill were later incorporated by Holland into his measure.

Those exemptions proved necessary last week when the committee voted to disregard Fairfax County's objections and order its magistrates to join the state system in July, 1982.

"Fairfax County has got to join the Commonwealth -- and don't be fearful," said Andrews. "You're gonna love what we're gonna do for you."