The polls say Israel is paying a significant price in American public favor for its invasion of Lebanon. Some American Jewish leaders anguish out loud about the Begin government's policies. There are rumblings of discontent in Congress. Is this the beginning of a fundamental change in the traditional, extra-special U.S.-Israeli relationship?

No -- or, at least, not yet. Much will depend on how Israel now reassesses its security requirements. With its northern border presumably secure and a peace treaty with its most important adversary, Egypt, to the south, the question is what effect this will now have on Israel's approach to the West Bank and Gaza, to the central Palestinian problem and the larger peace process.

That's the point: what is happening is not so much a shift in sentiment, from support for Israel to opposition, as it is a shift in the burden of proof -- a shift, even among Israel's most reliable backers, from unquestioning support to sharp questioning. By way of example, I offer in evidence a long letter to House Speaker Tip O'Neill from Rep. David Bonior, a young (37) liberal Democrat from Michigan's 12th district, reporting on his recent tour of Syria, Lebanon, Jordan, Egypt, and Saudi Arabia, as well as Israel.

His report to the speaker is his personal view. But it's the view of a self-styled "staunch supporter" who voted unfailingly for military and economic aid to Israel and publicly opposed arms aid to its neighbors, including the AWACs sale to Saudi Arabia. His trip, Bonior wrote to O'Neill, has "opened my eyes to another perspective."

To begin with, he was "somewhat startled by the intransigence of the current Israeli leadership," and particularly by the insistence of Prime Minister Menachem Begin, Defense Minister Ariel Sharon, and Foreign Minister Yitzhak Shamir that "Israel could eliminate the PLO as a political force in the Middle East." Bonior doesn't buy the implication that "by eliminating the PLO, the political problem will disappear," and he offered, by way of contradiction, a vivid anecdote:

He was surveying the rubble in West Beirut when an automobile drew up, carrying a Palestinian family. The father got out of the car and Bonior asked him if he lived in the neighborhood. The father pointed to a razed building and said that his son had been killed the day before and lay buried in the broken concrete.

Another son, 13 years old, was in the back seat of the car. When he learned that Bonior was an American, he flew into an almost uncontrollable rage. "(He) clearly identified the blame for his brother's death and for the bombing and destruction of West Beirut with the United States," Bonior recounted.

From this and other evidence, Bonior concludes that the "Begin-Sharon policies are radicalizing a whole new generation of Palestinian people. Far from eliminating the PLO and the Palestinian problem, they are enhancing it and creating additional recruits."

Bonior came away convinced that the Israelis did indeed use American military equipment in violation of the U.S. Arms Control Export Act, and he was not much impressed by Sharon's response to that suggestion: "His reply was in essence that there are many agreements with many countries and, during times of war, agreements can be broken."

Israel's performance in Lebanon disturbs Bonior on other grounds. He sees it not as a limited security measure but as a calculated Israeli effort to "rearrange Lebanese politics" in a way that will "not add stability in Lebanon, but instead plays into the hands of divisive forces" -- notably the Christian Phalange.

Bonior was also impressed by what he was told by his Arab hosts: that the tight U.S.-Israeli military connection has upset any "semblance of balance" in U.S. Mideast policy and threatens to damage American relations with Eqypt, Saudi Arabia and other "moderates." He said "several Arab leaders warned of the possibility of Soviet manipulation of the U.S. position."

Finally, Bonior (a Vietnam veteran) noted a "growing backlash" within Israel itself against the Begin-Sharon policies, not unlike the internal divisions in the United States over Vietnam. He cited violations of the rights of Palestinians on the West Bank and in Gaza ("the confiscation of property, imprisonment without charge, and lack of due process of law") and deplored the Begin government's consistent refusal to "make accommodation with moderate elements on the West Bank."

Bonior's biggest worry is that the Begin government is squandering Israel's most important political asset: its "moral edge in the ongoing struggle with Arab states."

"In conclusion, I would like to stress that I am still a strong supporter of the state of Israel," Bonior told the speaker. But almost every other sentence in his four-page letter raised questions about how long Israel can afford to gamble on the goodwill and strong support of a David Bonior.