The Virginia Senate, responding to what lawmakers said was growing public opposition, effectively killed legislation today that would have exempted legislators and many local government officials from criminal prosecution under the state's conflict-of-interest law.

"It's out of gas. It has four flat tires," said a grinning state Sen. Joseph V. Gartlan Jr. (D-Fairfax), savoring his victory over what had become the most debated measure of the 1986 legislative session.

Gartlan and others credited newspaper editorials and public opposition with killing the bill, supported by some of the legislature's most influential members. "I don't think there has been a groundswell of public opposition develop as quickly as this has in the 15 years I've been here," Gartlan said in an impassioned floor speech minutes before the Senate voted.

The senators voted 28 to 11 to strike from their calendar the House-passed ethics measure that had ballooned from a relatively innocuous clarification of the law to a major revision of the entire conflict statute.

Although the House of Delegates could attempt to resurrect the measure, House leaders conceded that they do not think they have enough support to pursue such an effort.

Some House members were more cautious, however. "It ain't over until the fat lady sings," said Del. Alson H. Smith Jr. (D-Winchester).

Sen. Clive L. DuVal II (D-Fairfax) said he spent much of the weekend trying to persuade "susceptible" colleagues to vote against the measure, arguing that the Virginia legislators risked being labeled "sleazy solons" by weakening the state's ethics law.

"It was just too much," DuVal said. "Our reputation was at stake."

"I was tired of hearing from y'all reporters and the public and those editorial writers," shouted Sen. William E. Fears (D-Accomack), explaining why he was one of 11 senators who switched sides on the issue today. "These editorials just stir up the people."

Sen. John C. Buchanan (D-Wise), who had argued that the existing conflict law is unconstitutional and should be changed, said the Senate buckled under "outside pressure, fear and confusion, a lot of ignorance and hypocrisy."

Buchanan, a physician from Southwest Virginia, said opponents of the weakened ethics law won the battle because "a lot of people wanted to get off the hook."

The General Assembly came under attack from virtually every daily newspaper in the state for its actions on the conflicts-of-interest law, especially after some legislators argued that the Virginia Constitution's "free speech and debate" clause protected them from criminal prosecution for some ethics violations.

"What would Thomas Jefferson, James Madison and other founders think of the Virginia General Assembly in 1986 using constitutional conjecture as camouflage to weaken its own, freely adopted, conflict-of-interest law?" questioned the Richmond Times-Dispatch. "Of elected Assemblymen acting like little George IIIs? We believe they would be flabbergasted and embarrassed."

Sen. Charles J. Colgan, the Prince William Democrat who supported the diluted ethics bill on its first vote in the Senate, found himself the subject of a stinging editorial cartoon in a hometown newspaper that depicted the senator -- who owns an airline -- flying high above the law.

"I think a lot of members felt they had lost the confidence of the public," Colgan said after today's vote. He said he supported arguments that the legislature should discipline its own members. "But my constituents don't agree with me."

The debate over conflicts of interest has dominated the 1986 General Assembly and has colored action on dozens of pieces of legislation. The sensitivity of lawmakers was heightened before the session began when criminal charges were filed against Sen. Peter K. Babalas (D-Norfolk), the fourth-ranking member of the Senate. Babalas, a lawyer who has abstained from voting on the ethics measures, is scheduled for trial May 20 on charges that he voted last year to kill legislation that would have adversely affected second-mortgage companies, including one that paid him $61,000 in legal fees. Babalas has said he is innocent of the charges.

Gartlan argued today that the legislature should await the outcome of the Babalas case to determine which side is correct over the constitutionality of the current ethics law. "We can end the guessing game with that decision," Gartlan said.

The legislative debates over the issue had become so complex and convoluted that many legislators said they were uncertain of its impact. At each step of the legislative process, lawmakers weakened the ethics proposal. First, the House made it more difficult to prosecute lawmakers for violating the ethics law and reduced the criminal penalties for those convicted of such charges.

Then the Senate, at the urging of House leaders, stripped away the criminal penalties and voted to allow the legislature to set up its own ethics panels that would police members of the General Assembly. The Senate also decided to give local government officials the option to establish internal ethics panels, precluding themselves from criminal prosecution.

Gartlan, during his plea for support in killing the measure, said of the tortuous path of the ethics bill, "Give us the opportunity to close a not-very-happy chapter in the life of the General Assembly of Virginia."

Staff writer Donald P. Baker contributed to this report.