A Virginia House of Delegates committee of lawyer-legislators performed today what has become a ritual killing of a bill designed to weaken the power of Democratic lawmakers to handpick state judges in their hometowns.

The bill, which would have set up a 15-member commission of nonlegislators to help select judges, was one of three measures having major impact on Northern Virginia that were defeated today. As expected, other House committees killed a measure repealing the state's 4 percent sales tax on food and a bill to allow voters to elect members of local school boards.

The judicial selection reform bill, which has been able to win support in the state Senate, was designed to eliminate much of the controversy surrounding the way Virginia's state judges are chosen. That selection process, which Republicans have branded unjust, has increasingly tarnished the image Virginia's lawmakers like to project as nonpartisan statesmen.

"The selection of judgeships, while supposed to be above the political arena, is one of the most political acts done here," Del. George W. Jones (R-Chesterfield) said last year. Five years ago Wyatt Durette, a Republican delegate from Fairfax County, called the judge selection process "one of the most flagrant abuses of representative government in Virginia today," a complaint that GOP legislators said today's vote indicates is still valid.

Republicans have threatened this year to boycott the election of judges by the legislature. The minority party members claim they are excluded from participating in the elections because Democrats, in a time-honored tradition, nominate the judges in party caucuses and then bind all Democratic legislators to vote for the winning candidates.

Critics of the present system charge that there is currently too much potential for conflict of interest. Lawyer-legislators may be instrumental in appointing a judge, for instance, before whom they will appear in court when the legislature is not in session. In that case, argue critics, there would be a natural sympathy on the part of the judge for the man who helped hire him.

The judicial selection bill killed today was sponsored by Sen. William Parkerson (D-Henrico) and supported by both the Virginia State Bar and the Virginia Trial Lawyers Association, whose members would have dominated the judicial commissions.

Opposing the bill was Virginia's NAACP and ACLU organizations as well as L. Douglas Wilder (D-Richmond), the Senate's lone black member.Wilder argued that an independent judicial commission would likely be dominated by white, male bar association lawyers who would have little motivation to recommend blacks or women for judgeships.

"There has never been a state bar association to recommend a black for anything," said Wilder, who has considerable influence under the present system to affect Richmond's judicial appointments. "They aren't going to put a black man on that bench, or a woman. Now you can talk about this being nonracial, but I'll tell you something. This is the South."

The repeal of Virginia's sales tax on food, another perennial measure here, went down to defeat in the House Finance Committee despite a plea from its sponsor, Arlington Democrat Warren G. Stambaugh. He argued that a gradual repeal over a six-year period of what he called "this truly hated tax" would decrease state revenues by only 3 percent.

But the committee voted down the bill 12 to 8, after hearing lobbyists from influential state food dealers and retail merchants' groups complain about added paper work costs that would result from the gradual repeal. The panel has on its docket several other food tax measures repealing part of the tax or setting up food tax credits for low-income families. But Stambaugh predicted that all would be defeated.

The House Privileges and Elections Committee this morning killed the school board election bill sponsored by Del. Mary A. Marshall (D-Arlington) after committee chairman John Gray (D-Hampton) successfully engineered a parliamentary maneuver combining Marshall's bill with three similar measures that had less support. All four went down 12 to 8.