WASHINGTON. — Washington -- Allegations of an ''October surprise'' in the 1980 elections present the Democratic leadership in Congress with an opportunity and a duty to do something right, something Congress hasn't done well since Watergate: conduct a major investigation of a potentially momentous scandal. Ironically, conflicts of interests posed by their campaign finances may cost the Democrats this chance.
Democratic leaders are daunted by the duty, and by the risk of another fiasco like the Iran-contra inquiry that turned up more hot air than smoking guns. Some Democrats are talking of establishing a body like the Warren Commission, named in 1963 to investigate the assassination of President Kennedy. This would not ensure a good investi- gation, but it would spare Democrats from blame for a bad one.
The wrong lesson was learned from the Iran-contra debacle. It's not that Congress is incapable of conducting an important investigation; rather, no investigation can proceed without risk of giving offense to those who would rather not be investigated. To forswear that risk is to give up the investigation. Yet that's exactly what the select committees on Iran-contra did. Rather than offend the government of Israel and its supporters in this country who fund congressional campaigns, they farmed out to the Israelis the task of investigating the Israelis.
The 1980 Reagan-Bush campaign feared that a joyous release of U.S. embassy hostages in Iran, an ''October surprise'' just before the November 4 elections, might benefit Jimmy Carter's image and re-election bid. The central allegation meriting an investigation is that Reagan-Bush forces set up their own surprise -- a conspiracy to pay off Iranian mullahs for delaying the hostage release until after it would be too late to help Mr. Carter's election. As matters turned out, the hostages were released upon President Reagan's inauguration, and within hours U.S. weapons were flowing to Iran.
If such a plot is uncovered, Presidents Reagan and Bush would be forever tarred in the view of history, even if they were out of the loop.
At bottom, the story is that the Iran-contra arms scandal began before Mr. Reagan's 1980 election. The tale involves a symmetry of shadow governments seeking power in each country -- the Reagan-Bush campaign in the U.S., and the Ayatollah Khomeini's mullahs in Iran. According to the allegations, these not-so-loyal opposition factions succeeded by manipulating each other to subvert the foreign policies of their own countries. Foiling the Carter administration's tentative deal to release the hostages served the goal of each shadow team.
In chaotic Iran, the religious fundamentalists sought to win the post-revolutionary power struggle. The radical mullahs could have feared that such a deal might legitimize the relatively moderate Iranian government of then-President Abolhassan Bani-Sadr by showing him able to operate on the world stage and deal with the ''Great Satan,'' America. On the table was release of impounded Iranian funds and arms, and U.S. help for Iran in its war with Iraq, which had recently invaded Iran.
In any investigation of the story, the roles of Israeli agents or nationals serving as intermediaries for Iranian arms and cash deals would be a key element. Israel, which had long been cooperating with non-Arab Iran, shipped millions, perhaps billions, in U.S.-made weapons to Iran after Congress banned such shipments in November, 1979.
If Democrats go forward with a formal inquiry into ''October surprise'' allegations, it might seem logical to name a select committee largely drawn from standing committees responsible for national security and foreign policy. But if the role of Israelis proves central to the investigation, that would be a mistake. These committees are dominated by members whose campaigns raise large sums of money from pro-Israel PACs.
Sen. Daniel Inouye, D-Hawaii, headed the Iran-contra inquiry. For his 1986 campaign against a token opponent who spent only $30,000, Mr. Inouye obtained $50,825 from pro-Israel PACs. On the House side, the inquiry was headed by Rep. Lee Hamilton, D-Ind., who raised $44,300 from pro-Israel PACs and only $24,000 from PACs representing other ideological causes in his last three elections, all of which he won by more than two-to-one margins. Similar sums were donated to most of the other Democratic members of the committees.
Pro-Israel PACs generally give cannily, to influence close elections where they can help elect friends and defeat foes. Only one senator so easily re-elected has ever received as much cash as Mr. Inouye from pro-Israel PACs. In 1988, they gave $61,000 to ZTC the majority leader, Sen. George Mitchell, D-Maine, who had appointed Senator Inouye to chair the panel, and who was
re-elected with a better than 4-to-one margin.