Republican leaders, stung by Democratic charges that the Reagan and Bush administrations have been responsible for the savings and loan debacle, struck back savagely yesterday, accusing congressional Democrats of happily accepting campaign contributions from "S&L crooks" and in return telling the thrift owners "to let their good times roll."

After being thrown on the defensive by renewed attention to the role of President Bush's son Neil in the collapse of a Denver savings and loan, National Republican Congressional Committee co-chairman Edward J. Rollins led the GOP counterattack in a sharply worded address yesterday to the annual summer meeting of the Republican National Committee in Chicago.

"If money is the mother's milk of politics, the Democratic fund-raisers who were getting rich by looting the S&Ls were the milkmen," Rollins said. "They delivered the goods right to the doorstep of the Democratic Party."

In Washington, House Republican Whip Newt Gingrich (R-Ga.) joined in the GOP effort to blame the Democrats for the S&L scandal. Saying he is "sickened by the stench of hypocrisy and corruption . . . coming from Democrats," Gingrich threatened to mount a campaign to have a special counsel investigate the role of current and former congressional Democrats in the thrift scandal.

Gingrich was reacting to an effort by Rep. Patricia Schroeder (D-Colo.) to get her fellow House Judiciary Committee members to endorse a call for a special counsel to investigate the collapse of the Silverado Banking, Savings and Loan in Denver, where Neil Bush was a director. The demise of the institution is expected to cost taxpayers about $1 billion.

Responding to the Republican attacks, Democratic National Committee Chairman Ronald H. Brown said the GOP "can't escape . . . the fact that George Bush, Ronald Reagan and their high-roller friends ran the government, designed the S&L policy and hand-picked the people that gutted the oversight agencies. They are now being forced to take responsibility for the greatest rip-off in American history."

Meanwhile, a leading Democrat on the House Banking Committee accused the Justice Department of dragging its feet on a criminal inquiry into the Silverado failure and strongly suggested the alleged reluctance stems from campaign contributions by a Neil Bush associate to the GOP.

The lawmaker, Rep. Frank Annunzio (D-Ill.), suggested delays in the inquiry could be linked to a contribution of up to $100,000 to the Republican National Committee by Kenneth M. Good, a business partner of Neil Bush who Annunzio said had defaulted on $32 million worth of loans from Silverado.

"What was the purpose of Mr. Good's contribution, particularly when it came only days before the {1988 presidential} election?" asked Annunzio at a Capitol Hill news conference. "Could it possibly be that it was a donation of hush money?"

Yesterday's round of charges and countercharges was part of an escalating orgy of fingerpointing over the S&L crisis by members of Congress and political operatives of both parties. The frenzy reflects a sudden upsurge of voter concern that many lawmakers found during visits to districts over the July 4 recess, and fears that public antagonism over the cost will play a major role in the November congressional elections.

In his pointed and detailed attack in Chicago, Rollins criticized a host of past and present Democratic leaders by name, citing alleged ethical lapses by Reps. Barney Frank (D-Mass.), Gus Savage (D-Ill.) and Washington Mayor Marion Barry as well as condemning former House Speaker Jim Wright (D-Tex.), former representatives Tony Coelho (D-Calif.) and Fernand J. St Germain (D-R.I.) for financial dealings that he said led to their departures from Congress.

Citing a study prepared by Common Cause, a lobbying group, Rollins accused Democratic leaders of blocking legislation that would have placed greater controls on the thrifts in exchange for campaign contributions.

"It's no accident that the Republican leadership didn't get money from the bad S&Ls," Rollins said. "That's because the S&L crooks knew which party voted to let their good times roll, and which party voted to bring an end to the predator's ball."

In a resolution tentatively approved by an RNC subcommittee yesterday, the party asserted that Democrats "continuously blocked GOP efforts to solve the problem."

Mayor Sue Myrick (R) of Charlotte, N.C., told RNC's executive committee that Republicans must seize the opportunity to convince voters that the blame properly lies elsewhere.

Ifill reported from Chicago.