After a fierce overnight lobbying effort by Virginia's banking industry, the state Senate reversed itself today and killed a proposal that would forbid banks from charging membership fees for the use of credit cards.

The abrupt about-face, coinciding with final passage of measures lifting interest-rate ceilings on bank and retail store charge accounts, was immediately denounced by some senators as the most graphic evidence yet of the power bankers have over the General Assembly.

"We've just handed these people everything," said Sen. Richard L. Saslaw (D-Fairfax) after the vote. "You know I want to keep our banks viable. But by the same token I don't think we should be giving away the commonwealth to these people."

On Wednesday the Senate had responded to calls to "help the consumer" by attaching an amendment to the interest-rate deregulation bill banning banks from retaining the $15 membership fees they began imposing on their 1.5 million MasterCard and Visa customers last year. The amendment's sponsors had argued that since the banks would now be free to charge unlimited interest rates, cardholders should at least be spared the burden of paying the membership fees.

But today, during a reconsideration of the bill requested by bank lobbyists, the same amendment was defeated after an angry debate by a 17-to-11 vote. Three senators who had voted for the amendment Wednesday voted against it today, while two others who had voted for it earlier abstained.

"I call it redemption through enlightenment," said Sen. Ray Garland (R-Roanoke), one of the three who switched votes. "The more I thought about it the more I concluded that it the amendment really didn't achieve very much, and secondly it would be going against the free market principle."

The two other switchers, Sen. Frank W. Nolan (D-Augusta) and Sen. Stanley Walker (D-Norfolk), gave similar reasons for changing their minds. Nolan said he concluded that banning the fees would only cause the banks to raise interest rates even higher for the "poor old little guy. It's going to hurt the consumer."

Walker said that "after reflecting on it, I decided that it the amendment did damage to the purpose of the bill so I changed my vote. This is one of the toughest issues we've had to face down here for a long time."

Many other senators said the reversal on the fee amendment never would have taken place had it not been for one of the most furious lobbying efforts of the session. Within minutes after Wednesday's surprise 16-to-15 vote for the amendment, Virginia Bankers Association lobbyists W.O. Pearce and Jack Edmonds began scouring the halls of the General Assembly, buttonholing senators in their offices and outside committee rooms. "They were all over the place," said Sen. Dudley Emmick (D-Fincastle).

Pearce and Edmonds argued that lifting the membership fees would defeat the purpose of deregulating interest rates, putting Virginia banks at a competitive disadvantage with those from out of state and would possibly even cause them to move their credit card operations out of Virginia. They also warned that they would use their influence with Gov. Charles S. Robb if the fee amendment didn't come off.

"They told me, 'We're going to have the bill vetoed because we just can't live without the fees,' " said Sen. Clive DuVal (D-Fairfax), who had sponsored the amendment.

The implied veto threat infuriated some of the amendment's supporters. "I find that kind of insulting," Saslaw said during the floor debate. "The implication is that they've got a pipeline up there."

Robb has consistently supported the interest-rate deregulation bill without any amendments and even sent a letter to the Senate before Wednesday's voting, urging its passage. A Robb spokesman said today that the governor "had played no active role" in the lobbying over the membership-fee amendment and declined to comment on the bankers' statements about a possible veto.

During the debate, Sen. William Fears (D-Accomac) waved around a copy of the Robb letter in urging defeat of the amendment and cited statistics provided by Pearce claiming that the state's banks lost $10 million last year on their credit-card operations.

"According to the bankers--and I don't know whether they're lying or not lying--if you take off these membership fees, they will lose $14 million in income they have now," he said.

The defeat of the amendment to ban fees concluded a lengthy campaign by the bankers that began after a House committee last year defeated another bill lifting the state's 18 percent interest ceiling on the unpaid balances of credits cards. Within weeks of that setback, the state's seven largest banks, led by the Richmond-based Bank of Virginia, began to impose the $15 annual membership fee.

An element in the bankers' efforts was more than $42,000 in campaign contributions last fall to members of the House of Delegates who overwhelmingly passed the credit-card deregulation bill last month without an anti-fee amendment. Garland, who is running for Congress this year, said that the prospect of bank contributions to his campaign was not a factor in his change of vote.

"Let's say, it hinged on this one vote; you're talking about, at the most, $5,000 and that's problematical," he said. "They'll probably give the same amount to both sides. The good politics were all on the side of going against the banks."