Sen. Daniel K. Inouye (D-Hawaii) summed up the hypocrisy of Congress last week when he said that business-as-usual is on trial before the Senate ethics committee.

The "Keating Five" are the only senators sitting in the dock. But if every member of Congress who ever did favors for a campaign donor was sitting alongside, there would be no one left to sit in judgment.

"I believe what is on trial here is not the five colleagues of mine, but the U.S. Senate, and for that matter, the Congress of the United States," Inouye testified before the ethics committee. His was less a plea for reform than a call for the committee to come down from its ivory tower.

His words should ring true for one man in that tower, Sen. David Pryor (D-Ark.).

Pryor is supposed to pass judgment on whether his colleagues erred when they went to bat for the out-of-control savings and loan industry and Charles H. Keating Jr., a generous campaign contributor. Yet Pryor, too, went to bat for the S&L industry and was so proud of it that he touted his action to the news media. What a difference a bailout makes.

Like many other senators, Pryor had S&L problems in his state in the mid-1980s. The Federal Home Loan Bank Board and its chairman Edwin J. Gray were trying to pull the thrifts out of the fast lane. In Arkansas, 27 of 37 thrifts were feeling the screws and they didn't like it a bit.

They complained to Pryor and, on Oct. 3, 1986, he wrote a high-pressure letter to Gray accusing the Bank Board of having "a deliberate system of harassment against many institutions in this state."

To make sure Gray knew he meant business, Pryor put a legislative "hold" on a bill that Gray needed to recapitalize the S&L deposit insurance fund. Pryor even made his letter public.

Gray was desperate for the recapitalization bill, and Pryor was one of the senators keeping Gray on a tight leash by holding up the bill. Gray has testified that he had to kowtow to senators to assure the passage of the bill.

Apparently Pryor has found the elusive line between himself and the others.

When our associate Tim Warner asked for Pryor's explanation of the facts, he got a quick and well-rehearsed reply. Pryor's defense is that the hold he put on the recapitalization legislation was merely symbolic. But Gray had no way of knowing how far Pryor would go to stifle the much-needed bill.

Before the ethics committee sat down to judge the Keating Five, Pryor says, he showed his 1986 letter to the committee leadership, which said it wasn't a reason for Pryor to step aside.

And Pryor asserts his letter did not name any specific thrift, nor was it linked to campaign contributions. That may be Pryor's biggest stroke of luck. In the three years before he wrote the letter, he had received almost $20,000 in campaign contributions from the S&L industry, including at least $10,900 from Arkansas thrifts and their operators. But Pryor's letter to Gray did not mention any particular thrift. In that he differs from the Keating Five, who openly took up Keating's cause.

That difference must be little consolation to one of the Keating Five, Sen. John McCain (R-Ariz.). He made mistakes, but at least he never lifted a finger to stop the desperately needed recapitalization.