Defenders of Barack Obama, and sometimes Obama himself, seem frustrated that some American Jews refuse to assume their traditional role of support for the Democratic presidential nominee. The Obama defenders are irked that not all Jews accept at face value Obama's expressions of devotion to Israel and commitment to her security.

Why can't these contrarians just take Obama at his word (he is a Zionist, he really is, they insist)? The answer is "1973."

But the explanation starts in 2008. Many Jewish Obama doubters are convinced that Israel faces a true existential threat unlike any in 35 years. From nation states like Iran, which threaten to destroy Israel, to Hizbullah and Hamas terrorists, Israel may in the next decade be pushed to the brink of its existence. Israel's failure to defeat Hizbullah in 2006 demonstrated the limits of Israel's historic military advantage.

With the spread of nuclear weapons and other deadly technologies a second Holocaust - that is, the annihilation of a substantial portion of world Jewry - is not out of the realm of imagination.

THESE OBAMA skeptics recall a similar time, 1973, when Israel also faced extermination. Prime minister Golda Meir had miscalculated Anwar Sadat's willingness to go to war and decided against a first strike against Egypt. The Arab nations attacked in October 1973, and within days Israel was facing defeat.

The Israelis went to president Richard Nixon with a request for a massive infusion of arms. The Defense and State Departments squabbled. Our European allies, who feared an oil embargo (and would refuse us bases to refuel our planes), inveighed against it, and the Soviets blustered. Many on Nixon's staff wanted to deny the request, or offer only token assistance. Don't antagonize the Arab states, they counseled.

Nixon persisted and, according to some accounts, doubled the amount of aid Israel had requested. Riding herd on the bureaucrats, Nixon repeatedly intervened to push the transports along. Informed about a dispute regarding the type of air transportation, Nixon at one point exclaimed in frustration: "Tell them to send everything that can fly." Over the course of a month US airplanes conducted 815 sorties with over 27,900 tons of materiel.

Israel was saved due to this massive infusion of military aid. Meir referred to Nixon with enormous affection for the rest of her life. Nixon, despised by many in the US, was hailed as a hero in Israel. And Nixon (who had garnered a minority of the Jewish vote in 1972) received little or no political benefit at home for his trouble, leaving office the following year.

SO WHAT does this have to do with Obama? The Obama skeptics do not for a moment believe that Obama, in the face of domestic and international pressure similar to what Nixon faced, would rise to the occasion at a critical moment in Israel's history and "tell them to send everything that can fly."

In every significant interaction in Obama's adult life with those who distain and vilify Israel - from Rashid Khalidi to Reverend Jeremiah Wright to Louis Farrakhan - Obama has demonstrated passive resignation and indifference.

He did not stand up to his friend Khalidi, the Palestinian activist, professor and former Palestinian spokesman whom Obama honored at a farewell dinner, and object to Palestinian invectives that Israel was an apartheid state. He did not recoil, until Wright insulted him at the National Press Club, from Wright when he learned that Wright considered Israel a "dirty word" and postulated that Israel had invented an "ethnic bomb."

He did not heed (or was oblivious to) public pleas from Jewish organizations to avoid the Million Man March that Farrakhan organized; nor did he years later leave his church when it honored Farrakhan. It took a hateful rant from another wide-eyed preacher against Hillary Clinton, just when Obama needed to cool intra-party animosities, to do that.

AND IF any further proof were needed, Obama's actions with regard to the Kyl-Lieberman Amendment, the measure to classify the Iranian National Guard as a terrorist organization, should settle the question of Obama's intestinal fortitude when it comes to Israel. An issue presented itself: a choice between, on the one hand, taking a stance against Israel's most vile enemy, Iran, and, on the other, appeasing the far Left of his own party.

Obama chose to satisfy the MoveOn.org crowd and opposed the amendment. The amendment would have been "saber rattling" and unduly provocative, Obama argued at the time. Senators Dick Durbin, Harry Reid, Hillary Clinton and three quarters of the US Senate voted for the amendment.

Once his nomination was secured, Obama told those assembled at the AIPAC convention that he supported classification of the Iranian National Guard as a terrorist organization, a move he well understood was important to Israel's security and to AIPAC's members. Yet under just a smidgen of political pressure during the primary race, he had not been able to muster the will to support a modest measure which inured to Israel's benefit.

IS THERE anything in all this to suggest that in a potential crisis, when much of the world would be pressuring him to let Israel die, Obama would push all the naysayers aside and demand to "send them everything that can fly"? There is not a shred of evidence to suggest that he would be beyond persuasion when it came down to Israel's survival. In fact, all the available evidence indicates that the opposite is true.

That does not mean Obama will not carry the majority of the Jewish vote. Jews are overwhelmingly Democratic, and it is certainly the case that for many American Jews the secular liberal agenda takes precedence over everything else in presidential politics.

For these voters, then, "1973" is not uppermost in their minds. Their devotion to liberalism is controlling, and for their own peace of mind they are willing to accept Obama's generic expressions of warm feelings toward Israel.

Indeed the temptation to believe in Obama's bland promises of support for Israel is a tempting one for liberal Jews. If they can convince themselves that he will be "fine on Israel," no conflict arises between their liberal impulses and their concern for Israel. The urge to believe is a powerful thing, especially when the alternative is an intellectual or moral quandary.