The case of the Keating Five is playing out in the court of public opinion as well as before the Senate Ethics Committee. And some senators fear that the larger audience could force the hand of the official tribunal.

The hearings have exposed a national television audience to day after day of detailed allegations about connections between campaign fund-raising and political favoritism. Viewers clearly do not like what they're seeing.The immediate concern for each of the Keating Five - Sens. Alan Cranston, D-Calif.; Dennis DeConcini, D-Ariz.; John Glenn, D-Ohio; John McCain, R-Ariz.; and Donald W. Riegle Jr., D-Mich. - is proving to the committee that he did nothing improper in behalf of Charles H. Keating Jr. and his now-failed Lincoln Savings and Loan Association.

But their gnawing fear is that the hearings will do little to convince the public that there are times when legislators may properly intervene with federal regulators in behalf of a constituent - even when the constituent, like Keating, helped generate huge contributions to political campaigns.

Further, some of the Keating Five worry that they may be tarred by a broad brush that obliterates distinctions among them, and that public pressure will lead the committee to be harsh with all of them.

Members of the Ethics Committee and senators not involved in the case are increasingly concerned that the hearings will merely fuel the fire of public discontent over the behavior of all elected representatives.

In particular, the testimony of former Federal Home Loan Bank Board Chairman Edwin J. Gray gave heartburn to many involved in the hearings.

Gray, who as the nation's top savings and loan regulator attended a controversial meeting with four of the senators on April 2, 1987, is perhaps the best-known accuser of the five senators.

He said that he was improperly pressured at the meeting to withdraw a bank board regulation limiting certain thrift investments in real estate and other enterprises that was being strongly opposed by Lincoln. And he alleged that DeConcini offered him a "quid pro quo" that Lincoln would change some of its controversial practices if the rule was abandoned.

However, Gray fired volley upon volley not only at the Keating Five but at Congress in general, charging that the system of campaign contributions was little more than bribery. "It's a case of too much money chasing too many politicians," he said on more than one occasion.

"Gray was continually allowed to throw mud at the institution broadside," said one person involved in the proceedings.

"It's terrible. . . . It's hurting everyone," said another.

From the tenor of comments by viewers of the cable television network C-SPAN, which is providing gavel-to-gavel coverage of the hearings, it would seem that such fears are well-founded.

A C-SPAN spokeswoman said that on a viewer call-in show Nov. 29 at the conclusion of Gray's testimony, the network's switchboard lit up with calls praising him. "People love Ed Gray. They think he's standing up for taxpayers."

Special counsel Robert S. Bennett reportedly recommended to the panel that Glenn and McCain should be cut loose. But the Ethics Committee rejected that course.

"We should have taken the special counsel's advice," Sen. Trent Lott, R-Miss., said. He noted that two constituents - an older woman and a younger man from different parts of Mississippi - each told him to "hang 'em high," referring to all five. He said he was struck - and troubled - by their use of the same phrase.