THE MEMBERS OF the United States Senate are miffed, no doubt about it.

They are deprived of those daily ego-boosters that are to be found in hearings, meetings with constituents, lobbyists and White House calls.

They must sit hour after hour, closeted in the chamber, listening to the sordid story of one of their number who got caught. They are privately annoyed with Sen. Harrison Williams of New Jersey, who has moved among them for 24 years and never before made heavy claims on their attention, their sympathy or their self-interest.

"Why," they groan, "doesn't he resign and get it over with?"

But they have another rage of almost equal intensity, and it is against the FBI, which went window-shopping for potential criminals on Capitol Hill and added a senator to its loot.

They can be irritated at Harrison Williams, and his seven meetings with the Abscam crew, and his weakness and folly only until you read about Mel Weinberg, the Abscam master, who is so appalling a human specimen that the idea that any of them could end up with their fate in such hands makes their blood freeze and boil at the same time.

If Williams' story is sordid, Weinberg's is squalid.

Why did the FBI pay him a total of $133,150.82 for no visible purpose except to prove that Richard Nixon was right when he claimed that everybody does it?

Why was the Department of Justice using a convicted felon as divining rod on the "pre- disposition of evil" among members of Congress.

Sen. Daniel Inouye (D-Hawaii), Williams' defense counsel, stood up in the chamber last Wednesday, while the hammer blows of the crushing summation to the jury delivered by Sen. Howell Heflin (D-Ala) were still echoing in the chamber.

"I suggest that the FBI," he said,"offered more than an opportunity. I suggest that the FBI created a trap and then goaded and cajoled members of Congress into that trap."

"I think," he said levelly to his colleagues, "that it could happen to any one of us."

Democratic Leader Alan Cranston (D- Calif.) interrupted Inouye's discussion to demand a full Senate investigation of executive branch misconduct. Republican Whip Ted Stevens of Alaska put his name on the bill.

The Senate can reject Williams' pathetic plea that he was Oliver Twist to Weinberg's Fagin, and still insist on finding out what the FBI thought it was doing with its bankroll, its yachts, its fake sheiks, its bugs and cameras, sleuthing on crimes it was in the process of creating.

FBI Director William H. Webster, who is considered the choirboy of high federal officialdom, at a House hearing held in the wake of the astonishing disclosures, offered the most cursory justification of the sleaziness of the approach. Philip Heyman of the Justice Department spoke of the "precautions" taken in the targeting. But Inouye cited the off-the- cuff agreement to try to get Sen. Strom Thurmond on the say-so of Rep. John Jenrette.

Williams, he walked into their parlor uninvited. He attended a fund-raiser, where he encountered the Mayor of Camden, Angelo Errichetti, who by all accounts is not a finicky person in the ethical sense, was told of some Arabs, and asked to hear more.

Heflin pointed out that Williams did not need to meet the crew seven times to find out its quality. One whiff of Mel Weinberg, the Abscam spider and an individual of almost epic repulsiveness, should have been enough.

The senators should call Weinberg, who once described himself as "the world's biggest liar" to his long-suffering wife, to the Caucus Room. They should ask about his sales of used furniture, his wife's fur coat, his son's bicycle to FBI agents, who apparently used the Abscam yacht for trysts he arranged for them. He treated his wife Marie in a manner so disgusting as to make that other contemporary symbol of chauvinist callousness, Dr. Irving Tarnower, seem a model of knightly chivalry.

That was probably not the Senate's business until it fell to expelling Williams on Weinberg's account. And since Marie knew and confided to Jack Anderson much about her husband's financial dealings with the FBI, her suicide on Jan. 28 is a proper subject of inquiry. Weinberg's almost immediate remarriage may not be entirely relevant, but it adds to the picture.

Weinberg bragged in open court that he never paid a cent of income tax on the $133,000 we paid him for running a crime- school on Capitol Hill. We taxpayers are entitled to know why.

Thomas Puccio, the chief Abscam prosecutor, should be asked about a contract for an Abscam book that he negotiated while he was closing in on the made-to-order felons.

If is possible for senators to divorce FBI misconduct from Williams' -- and Sen. Heflin said they must -- it is just as possible, and even more imperative, to separate Williams from the FBI, and to expose the excesses of the G-men who measured the Congress for morality.