As the Senate debated a proposed $354 million arms sale to Saudi Arabia early Tuesday night, Sen. Rudy Boschwitz (R-Minn.) invited two of his colleagues to meet a friend.

In an ornate reception room off the Senate floor, he separately introduced Phil Gramm (R-Tex.) and Daniel J. Evans (R-Wash.) to Michael R. Goland, a wealthy California real estate developer.

Making the introductions, Boschwitz made sure that Gramm and Evans understood that his friend was not only very rich and strongly pro-Israel but was the Michael R. Goland who in 1984 spent more than $1 million of his own money to help defeat then-Sen. Charles H. Percy (R-Ill.), largely because he disagreed with Percy's views on the Middle East.

Goland, according to sources who confirmed the substance of the conversations, urged the senators to vote against the arms sale. Imagine the political impact, he told at least one of them, of a television commercial showing the wreckage of a civilian aircraft shot down by a Stinger antiaircraft missile, the most controversial weapon in the proposed arms package for the Saudis.

The message was clear: A vote to supply these arms to the Saudis could come back to haunt a politician. And, while Gramm and Evans remained firm in supporting the sale, they were in a distinct minority as the Senate voted, 73 to 22, to reject it. The next day, the House did the same, by 356 to 62, marking the first time a Congress has voted to block an arms sale.

Those unexpectedly lopsided votes were "a tribute to the appeal and strength of the Israeli cause" in Congress, said Rep. Henry J. Hyde (R-Ill.), a sale supporter.

Although the Israeli government and the main pro-Israel lobbying organization, the American-Israel Public Affairs Committee (AIPAC), did not wage a full-scale campaign against the arms package, Hyde noted, the pro-Israeli instinct in Congress is now "so strong and so pervasive, it was really no contest."

Several factors have contributed to this, including growing public disenchantment with the Arab states of the Middle East. Not the least of forces at work whenever Middle East policy becomes an issue in Congress is the increasingly active and powerful role of pro-Israeli political action committees (PACs) in campaign fund-raising.

Basing their fund-raising activities solely on candidates' attitudes toward Israel and the Arab states, these Jewish PACs contributed $3.5 million to political candidates in the 1984 elections, almost double the amount they gave in the 1982 elections.

In 1984, Goland introduced a new and potentially foreboding element into the mix -- the role of the free-lance campaign finance operative, willing to make legally unlimited, "independent" expenditures on television, direct mail and billboard advertising to defeat a candidate he views as anti-Israel.

These pro-Israeli activists have not always been successful, either in swaying individual senators or electing their chosen candidates. With campaign costs growing each election year, however, they cannot easily be ignored, particularly since so little political gain is possible voting against their wishes.

"I understood the politics of it," Gramm said of his conversation with Goland. "You have some people who feel very strongly about" the arms sale, "are against it, while the rest of the public doesn't care. Nobody else knows or cares about it."

Nor are pro-Israel members of Congress timid about suggesting that the potential pitfalls of being perceived in the Jewish community as less than a friend of Israel. Alan Cranston (D-Calif.), who led sale opposition, said he expects few opponents to switch sides when the Senate attempts to override President Reagan's expected veto of the disapproval resolution.

Cranston recalled the case of then-Sen. Roger Jepsen (R-Iowa), who in 1981, under intense Reagan administration pressure, reversed his public position and voted for sale of five Airborne Warning and Control System (AWACS) reconnaissance planes to Saudi Arabia.

In 1984, Jepsen, like Percy, was defeated. His switch had been a major campaign issue, although not the only one. The Jepsen example "has sort of struck terror into the hearts of senators about switching" on these closely watched Middle East policy votes, Cranston said.

In this atmosphere, the normally pro-Israel instincts of most lawmakers have taken on an institutional life of their own in Congress.

It is exactly what AIPAC Executive Director Thomas A. Dine hoped for. Dine moved aggressively then to build his organization's grass-roots support, swelling its membership ranks, while the number of Jewish PACs focused on issues involving Israel was rising dramtically.

Now, the combined political force is so strong that these groups did not have to lobby actively to win a victory over the administration.

"They have created a presence," said Rep. Tony Coelho (D-Calif.), chairman of the Democratic Congressional Campaign Committee. "It's like the NRA [National Rifle Association] and others. They don't have to lobby on things. People are looking for ways to please them or not get in trouble with them."