The Federal Election Commission has ruled unanimously that there is "insufficient evidence" to believe the American Israel Public Affairs Committee (AIPAC), the nation's top pro-Israel lobby, controls a group of political action committees (PACs) that give millions of dollars to congressional candidates.

The six FEC members voted a year ago, but the result was not released then because part of the complaint was and is still pending. A partial disclosure was made yesterday because the PACs have been waiting so long for a resolution, an FEC spokesman said.

The ruling is significant because if the FEC had agreed the groups were "affiliated" they would have been counted as one PAC and limited to giving $10,000 to a candidate during an election cycle. During the most recent election cycle, several senators received more than $200,000 each from pro-Israel PACs. The FEC made such a ruling against the American Medical Association years ago.

David Ifshin, a Washington attorney who is AIPAC's general counsel, said in a statement that the decision "finally puts to rest the steady stream of unfounded allegations concerning AIPAC's legitimate activities."

AIPAC is not a PAC and makes no political contributions. But it is one of the most effective and feared lobbies in Congress because of its ability to get foreign aid money for Israel, block arms sales to Arab nations and help or hurt U.S. politicians.

Richard Mayberry, attorney for seven former U.S. officials who filed the complaint last year, said he was "shocked and surprised" that the FEC decided to close part of the case without questioning witnesses or subpoenaing documents. The FEC ruled after AIPAC and the 27 PACs filed voluminous affidavits and exhibits.

Mayberry said his clients might challenge the ruling in federal court. Such decisions are rarely overturned.

"AIPAC is not home free," Mayberry said, because the remaining issue in the case appears to be the allegation in the complaint that the lobby is an unregistered political committee, which made illegal corporate expenditures in support of candidates.

"The remaining issue in the complaint is a technical matter AIPAC fully expects to be be resolved in its favor," Ifshin said. "Any assertion to the contrary is wrong."

But, Mayberry said, "If it was a technical issue, it would have been decided and everything released a year ago."

The complaint, filed with the research help of the Arab American Anti-Discrimination Committee, cited a number of newspaper and television reports about AIPAC's political activity. One was a 1988 Washington Post story, based on internal AIPAC documents, which said the group's deputy political director, Elizabeth Schrayer, tried to steer PAC donations to certain Senate candidates in the 1986 elections.

That practice contradicted AIPAC's policy of not rating or endorsing candidates. The group said in its response to the complaint that the Schrayer memo was a rare exception to its stated policy but was a legal "communication" because the contacts were with other AIPAC members at the individual PACs.

In analyzing the complaint and responses, FEC lawyers noted that Schrayer's efforts were "offset" by the fact that some of the PACs contacted gave to the opposite candidate.

In his 103-page report on the "affiliation" question, FEC General Counsel Lawrence M. Noble was convinced by the responses from AIPAC and the PACs that the lobby did not establish, finance, control or maintain the PACs.

Overlap in membership was insignificant, his report said. And it noted that the PACs often give to the same candidates because they are single-issue groups disposed to donate to pro-Israel supporters in Congress.

The release puts on the public record more about the inner workings of the larger pro-Israel PACs than has been known before. It shows, for example, that a few of the PACs give only to Democratic candidates. Several, including the largest, the 58,000-member National PAC, have formal or informal executive boards that decide which candidates to aid. In some, one individual makes all the contribution decisions.

FEC spokesman Scott Moxley said that because of the FEC's limited resources, it is not unusual for the FEC to rule without opening its independent inquiry.