She warned him. She told him in person and on paper that Charles H. Keating Jr. was bad news. But Laurie A. Sedlmayr was the staff member and Dennis DeConcini was the senator, so they did what he wanted, and it has all turned out much worse than even she expected.

It's an old story about the employer overbalanced by the employee, not just on Capitol Hill, of course, but in books and plays that never fail to delight. James M. Barrie's "The Admirable Crichton" springs to mind, and P.G. Wodehouse's wonderful saga of Jeeves and Bertie Wooster.

Sedlmayr is, to all appearances, your model legislative assistant. A dark blonde, her clothes, her manner, her speech proclaim the self-effacing, level-headed aide, looking around corners in an effort to save her principal from himself.

Her boss may have known that Keating was big trouble, that he was insatiable in his demands for action to make the world a safer place for Lincoln, his savings and loan. It did not take a Rhodes scholar to see that the owner of American Continental Corp., parent of the S&L, treated senators like office boys. "More extreme in using the system," as Sedlmayr discreetly put it, "a highflier."

"I found him to be something of a zealot," she explained under questioning from the Senate ethics committee special counsel, Robert S. Bennett. "I think the senator thought I was overstating the case."

Actually, the senator almost had to think she was. He had to raise money in order to stay in the Senate, and Keating was a big giver, also a big honcho at home. American Continental employed more than a thousand people in its Phoenix headquarters.

Arizona's other senator, John McCain, also was expected to salute Keating, who was a friend. He too had a farseeing assistant, the estimable Gwendolyn van Paasschen. She tried to protect McCain from the octopus-like embrace of Keating, and succeeded up to a point. McCain had received larger campaign contributions from Keating than DeConcini had. Van Paasschen, nonetheless, spoke her mind when DeConcini tried to inveigle McCain into going with him to the office of Federal Home Loan Bank Board Chairman Edwin J. Gray to plead for Lincoln.

"It was my view and I told Senator McCain . . . that it was my view that what Senator DeConcini had suggested was inappropriate," she told the committee.

The two women met often for what Sedlmayr called "mutual discussions." They probably sounded like two nannies in a park, clucking over their wayward charges.

Van Paasschen had what the "Keating Five" lacked: a seemliness barometer. She prevailed upon her principal not to go begging to Gray, but he slipped away to two famous meetings, one with Gray and the other with regulators from California who had the unenviable task of keeping Keating in line.

McCain has won points, along with Sen. John Glenn of Ohio, a certified innocent who is thought to be the victim of an overeager staff, for severing all ties with Keating once the "criminal referral" flag was raised.

What emerged from Sedlmayr's reading of various memos and letters she had written -- some in her own name, some in the senator's -- is that nothing Keating asked was too much.

Keating wanted a hearing on a rule forbidding S&Ls to make direct investments; DeConcini fired off a letter to a Senate committee chairman, calling the proposed ban "arbitrary and premature." Keating spewed complaints about Gray; DeConcini ferried them to the top -- to Donald T. Regan and James A. Baker III. Keating wanted to replace Gray with Lee Henkel Jr., who owed the Lincoln S&L "millions of dollars"; DeConcini lobbied the White House in his behalf, although Sedlmayr testified he had never met the man.

At one point, Bennett asked Sedlmayr why she had been concerned about the meeting with Gray that DeConcini had arranged. "I thought it might be misinterpreted by the press," she said diffidently. "I thought it might come out being a political mistake."

"Why?" asked Bennett.

"Well," she replied dryly, "we're here."

Maybe one consequence of the multiple embarrassments of the "here" could be that senators will in the future heed the good counsel of the women they hire to warn them about rocks ahead.