The strongest advocates of closing the "revolving door" connecting Pentagon procurement officials with defense contractors used to blame the system - not the integrity of individuals - for problems in military purchasing.

But a growing bribery investigation indicates the problem is even worse than imagined by the critics, who have long sought ways to curb the departure of top Pentagon officials for jobs with companies doing business with the Defense Department.A search warrant revealed Thursday that the government is investigating the "bribery of public officials" as part of a scheme in which defense contractors got inside information from former government officials whom they had hired as consultants.

Now, the integrity of individuals is under attack as well as the system, in which the Defense Department relies on a small number of large contractors - whose main business is selling to the Pentagon.

This lack of competition "blurred the healthy distinction between buyer and seller, and this is vividly illustrated when we look at the problem of the `revolving door,' " Rep. Barbara Boxer, D-Calif., said in congressional testimony in 1985.

She said that as the numbers of high-ranking government officials moving to defense contractors increased, the interests of the Pentagon and the corporate suppliers merged.

"The real problem with an environment that stresses cooperation between contractor and government is that no one is watching out for the taxpayer," she said. "The result is a procurement system in which price is the least important factor."

But she added, "One thing is clear: The integrity of individual procurement officials is not the issue. What is important is an existing employment pattern that does not protect the public against the misuse of its tax dollars."

Thursday, as new information on the latest scandal became public, Boxer recognized the change.

"Now, it is bad enough that such a situation undermines public confidence in the procurement system," she said in a floor speech. "It is far worse to learn that former and current public officials may have broken the law in a rush to cash in on the contracts that they gained at taxpayers' expense. Nothing could be lower than that."

And in a letter, she asked the Defense Department inspector general's office to determine whether there is cause to believe that any former Pentagon official who walked through the revolving door violated a 1987 law.

The law prohibits former top Pentagon employees or military officers from accepting pay from contractors for a two-year period in jobs involving defense procurement.

The law includes civil fines of up to $250,000 for ex-government officers who violate the provision, and up to $500,000 for anyone who offers or actually pays compensation to the ex-official - while knowing such compensation violates the law.

The law does not apply to companies with contracts of less than $10 million.

The Senate tightened the noose last April. By voice vote, it passed ethics legislation that said top executive branch officials, including generals and admirals, could not lobby the executive branch or members of Congress for a year.

A House Judiciary subcommittee, headed by Rep. Barney Frank, D-Mass., is working on its version of the legislation.

A 10-year-old law makes it a crime for an executive branch official to lobby his or her former agency within a year of leaving the agency.

How bad has the problem been?

A General Accounting Office study in 1986 said more than 20 percent of the people who left jobs at the Pentagon in 1983 and 1984 to join defense contractors were spending at least some time working on the same projects they had previously overseen.