Sen. Dennis DeConcini (D-Ariz.) told the Senate ethics committee yesterday that lawmakers should not have to worry about an appearance of impropriety if it keeps them from helping home-state "special interests" that have been wronged by government.

"You can't afford to be terrorized by an appearance standard that would prohibit somebody from intervening for some special interest in their state, {such as} some agricultural interest in their state, that is not getting a fair shake," DeConcini said in response to questions about his ethical standards.

A key question before the ethics panel is whether to consider appearances as well as actual conduct in weighing the cases of five senators who intervened with federal regulators on behalf of savings and loan executive Charles H. Keating Jr. Keating raised more than $1.3 million for their campaigns and causes during the period in which he was seeking their help.

Keating's Lincoln Savings and Loan was located in California, but Keating lived in Arizona, where Lincoln's now-bankrupt parent corporation, American Continental, was headquartered. Keating raised $31,000 for DeConcini's 1982 campaign and $48,000 for his 1988 reelection campaign. The S&L executive also served on DeConcini's campaign finance committee in 1988.

In addition to DeConcini, the senators under investigation by the committee are Alan Cranston (D-Calif.), John Glenn (D-Ohio), John McCain (R-Ariz.) and Donald W. Riegle Jr. (D-Mich.). The committee is hearing final testimony by the senators and is expected to wind up two months of hearings in the case next week.

Robert S. Bennett, the committee's special counsel in the case, has argued that an appearance of wrongdoing undermines public confidence in the Senate's integrity and may constitute a violation of its ethical standards. Apparently relying on both conduct and appearance standards, Bennett recommended last year that the committee proceed with probes of Cranston, DeConcini and Riegle but take no further action against McCain and Glenn.

But the committee has not indicated how broadly it interprets the standards, and some of the five senators, including Riegle in testimony earlier this week, have said lawmakers should not be disciplined for improper appearances if their conduct was proper.

In testimony that is expected to continue today, DeConcini repeatedly denied any improper conduct, including his intervention on Keating's behalf.

"I know where the line is, and I don't cross it," he said, saying the line is drawn at such things as taking gifts in exchange for legislative favors or threatening or taking retaliatory action.

"But I am an activist and I do intervene. . . . I believe the government is wrong sometimes, and we {Congress} are the last resort" for constituents who have a grievance against their government, he said. A lawmaker must "have the courage to stand up to government when it is wrong and to tell a constituent when you think it is right," he added.

One of the key points at issue in DeConcini's case is whether he attempted to negotiate a deal on Lincoln's behalf at two meetings that the senators held with thrift regulators in his office in April 1987. Some of the regulators said he had proposed a deal in which the regulators would ease up on investment restrictions in exchange for Lincoln's agreement to make more home mortgage loans and described the atmosphere of the meeting as intimidating.

DeConcini denied attempting to negotiate a deal for Lincoln, saying the senators were in no position to do so because they did not even know what the regulators' position was.

Even if he had chosen to negotiate on Lincoln's behalf, it would not have been improper, DeConcini asserted. "I know of no rules that you can't negotiate on behalf of a constituent . . . but this was no negotiation," he said.

When his attorney, James Hamilton, asked whether anything occurred that would have been intimidating to the regulators, DeConcini replied, "Of course not." Several of the regulators, including Edwin J. Gray, former chairman of the Federal Home Loan Bank Board, described the atmosphere of the meetings as intimidating.

In sometimes testy responses to questions from Bennett, DeConcini referred to him as the "special prosecutor," as he did when he presented his opening statement to the panel in November.

Disagreeing with his colleagues on some key points, DeConcini suggested that Riegle played more of a role in laying the groundwork for the first meeting with regulators than he portrayed in testimony Monday. After Keating suggested that he contact Gray about setting up a meeting with senators, DeConcini said he asked Riegle for his view and quoted Riegle as saying he thought it was a "good idea." Riegle has denied any role in setting up the first meeting, which he did not attend. He attended the second meeting a week later.

Although McCain indicated he had reservations about the meeting, DeConcini said he got just the opposite impression. In opening questions about his social relations with Keating in Arizona, Hamilton also asked DeConcini if he had ever taken trips with Keating, a reference to trips taken by McCain and his family on Keating's corporate airplanes. No, DeConcini responded, he had taken no such trips.