Robert J. Thompson, a Republican lobbyist and former White House aide who had virtually no experience in the banking industry, said yesterday that he was hired to help arrange a controversial purchase of government-owned savings and loan institutions because he knew how to get things done in Washington.

In an interview yesterday, Thompson confirmed that he was promised an undisclosed share of the profits for his part in aiding Arizona businessman James M. Fail acquire 15 bankrupt Texas savings institutions, now called the Bluebonnet Bank of Dallas. Fail, who stands to receive $1.85 billion in federal subsidies, put up only $1,000 of his own money in the 1988 transaction, which has been called the "worst case" of abuse in the nationwide S&L scandal by Sen. Howard H. Metzenbaum (D-Ohio).

"Jim Fail asked us to help him understand the process," said Thompson, who heads a Washington lobbying firm. Thompson, a former aide to then-vice president George Bush, said he arranged for meetings between Fail and government officials, including some he had met while working for the Reagan administration, but denied using his former connection to Bush to help his client.

In return for his help, Thompson said, Fail paid him a lobbying fee, arranged a $150,000 loan and promised to give him 2 percent of any profits he made from Bluebonnet. The government subsidies allowed Fail to make a 62 percent return on his investment last year, the highest rate of profit in the thrift industry.

Thompson's role in helping Fail buy Bluebonnet has been highlighted by Metzenbaum in his investigation of alleged political influence in the savings and loan debacle, which is now projected to cost taxpayers $300 billion.

Thompson said yesterday that he will refuse to respond to a subpoena to testify today at a hearing before the Senate antitrust subcommittee chaired by Metzenbaum. Calling the hearing "a rigged game," Thompson said, "Senator Metzenbaum is not interested in fair play or the truth about the Bluebonnet transaction. He is interested only in headlines."

Metzenbaum yesterday asked Sen. Joseph Biden (D-Del.), chairman of the Senate Judiciary Committee, to schedule a vote for Thursday on compelling Thompson to comply with the subpoena.

In spurning the subpoena, Thompson sought to take the offensive, describing his version of the Bluebonnet story in a two-hour interview. At Thompson's side were Stanley M. Brand, a Washington defense attorney; Robert L. Meuser, general counsel of Thompson's firm, Thompson & Co.; and Lance Morgan a vice president of Robinson, Lake, Lerer & Montgomery another Washington lobbying firm.

Brand said Thompson is refusing to comply with the subpoena because Metzenbaum's subcommittee is exceeding its jurisdiction by probing Thompson's personal and business finances and has violated his privacy by leaking confidential information to the media.

Thompson said he first became aware of the business potential for working with investors seeking to purchase failed financial institutions from a cousin in Oklahoma who had been involved with taking over failed banks from the Federal Deposit Insurance Corp.

It was also through his cousin, Thompson said, that he met Fail, a Phoenix executive who had made millions by purchasing ailing insurance companies and rebuilding their financial health.

Thompson said Fail first hired his firm and paid $65,000 for help in purchasing a small Oklahoma City bank from the FDIC.

He said he played a much larger role in helping Fail arrange the Bluebonnet transaction, one of dozens of S&L takeovers that were engineered in 1988 by M. Danny Wall, then chairman of the Federal Home Loan Bank Board. Thompson said he got to know Wall when he was a White House lobbyist in the early years of the Reagan administration and Wall was a top Republican aide in the Senate.

"We became the project managers" Thompson said, helping investment bankers, accountants and lawyers for Fail work with thrift regulators in Washington, Dallas, Atlanta and New York on a complex deal.

Thompson said he was paid a retainer by Fail and in addition confirmed that he negotiated two special forms of compensation that are now the target of not only Metzenbaum's congressional hearings but also an investigation by the state insurance regulators in Arizona, where Fail's companies are headquartered.

The lobbyist said Fail orally promised to give him and two other people a share of any profits that were made on the purchase of Bluebonnet.

Thompson said he has received no money from that arrangement because Bluebonnet has not yet paid any dividends to the holding company owned by Fail.

The promise of a share of the profits to Thompson may have violated government regulations and policies for handling the sale of failed financial institutions, government officials said yesterday.

The Federal Home Loan Bank of Dallas, which was in charge of the Bluebonnet sale, had a well-publicized policy of forbidding any bonuses or "finders fees" from being paid in connection with restructurings of failed thrifts, officials said. The FDIC, which now has responsibility for the 1988 thrift sales, prohibits the payment of contingent fees to investment bankers, lawyers and advisers in government-assisted transactions.

Thompson said the promise that he would get a share of the profits was not disclosed to federal regulators because it was "a contractual arrangement" with Fail rather than a part of the thrift purchase.

A loan arranged for Thompson by Fail is being investigated by Arizona authorities, said Susan Gallinger, director of the Arizona Department of Insurance.

Thompson said an insurance company controlled by Fail agreed in January 1989 to guarantee a $150,000 loan from an Oklahoma bank. Three months later, the insurance company paid off the bank and took over the loan. The insurance company in turn transferred the loan to Fail's holding company, after state regulators said the loan appeared to violate restrictions on the kinds of investments insurance companies are allowed to make.

The borrowing, Thomkpson said, was in the form of an unsecured personal loan. Arizona insurance companies are generally prohibited from making unsecured personal loans, Gallinger said. State regulations also prohibit insurance company executives from having a financial interest in investments made by their company, she said. Documents turned over by Thompson to Senate investigators describe the loan as part of his compensation for work on the Bluebonnet transaction for Fail, which could indicate he had a financial interest in the transaction, an attorney familiar with the transaction said.

Thompson said $50,000 of the $150,000 was used to purchase a half-interest in a 10-acre horse farm from Rep. Doug Bosco (D-Calif.), whom he described as a longtime family friend. The other $100,000 was invested in a limited partnership headed by Paul G. Heafy, a former FDIC official in Oklahoma.