As the Iran nuclear talks head down the home stretch, it is increasingly obvious that Secretary of State John Kerry’s comments about walking away from the negotiations if a “good agreement” isn’t obtained are not credible. A deal or, as Omri Ceren predicts, a “non-agreement agreement” is inevitable even as the deadline was extended to the end of the week. That means the focus will soon change from the standoff in Vienna to Washington where a Congressional debate on the deal that comes out of this process will soon begin. The result of a vote on the deal is by no means certain but most observers believe that although there will be majorities in both Houses that will vote against it, opponents will fall well short of the two thirds they need to override President Obama’s expected veto. Such an outcome will be made possible by the decision of a critical mass of Democrats in the Senate and especially the House to back the president’s deal even though it will not satisfy the administration’s own stated goal of preventing the Islamist regime from getting a weapon. If so, that will be explained by partisan loyalty and the hold the president still has over much of his party. But there’s no escaping an answer that is just as obvious that was highlighted in a new poll conducted by Frank Luntz that was reported today in the Times of Israel that sees Israel losing Democrats across the board.

It should not be forgotten that the issue of the nuclear threat from Iran transcends that of support for Israel. A nuclear Iran or even one that has attained the status of a threshold nuclear power with Western approval — which the president’s deal will assure — presents a clear and present danger to the Arab world, including U.S. allies like Saudi Arabia as much as it does to Israel. The boost such an outcome would give terrorist groups allied with Iran, such as Hezbollah, Hamas, and the Houthi rebels in Yemen as well as the Assad regime in Syria would undermine the regional balance of power and help Tehran in its quest for regional hegemony. Moreover, Iranian nukes are also a threat to the United States and Europe, especially if Iran’s ballistic missile program is not halted; an aspect of the problem that the agreement is as unlikely to address as the regime’s state sponsorship of terror.

But there is no ignoring the fact that it will be the pull of the alliance with Israel that will determine more votes in Congress than general qualms about regional or even U.S. security. The existential threat to Israel from an Iranian weapon is obvious, a point brought home again today by the published comments of former Iranian President Rafsanjani who repeated what many others in power — including the country’s Supreme Leader — have already said: that Israel “will be erased soon.”

If Democrats are going to buck Obama, it will be because their instinctual support for Israel makes it impossible for them to vote to approve a weak nuclear deal that, as this one does, provides Iran with two paths to a bomb: one by cheating on its easily evaded rules and one by patiently waiting for it to expire in ten years.

But if, as Luntz points out, a growing number of Democrats are ready to abandon Israel, it will be that much easier for the White House to rally the president’s party behind a détente with Iran that he considers integral to his foreign policy legacy.

Luntz’s poll, which was sponsored by the Jewish National Fund, is consistent with other surveys that have showed a growing gap between Republicans and Democrats about Israel. But the highlights he provided still ought to shock pro-Israel Democrats:

* 76 percent of Democrats but only 20 percent of Republicans say Israel “has too much influence” on U.S. foreign policy.

* Asked whether Israel was a “racist country,” 47 percent of Democrats agreed, 32 percent disagreed and 21 percent either didn’t know or were neutral. By contrast, 76 percent of Republicans disagreed while only 13 percent agreed and 12 percent didn’t know or were neutral about this canard.

* When queried as to whether Israel wanted peace, only 48 percent of Democrats agreed while 31 disagreed and 21 percent didn’t know or were neutral. By contrast, 88 percent of Republicans agreed while only five percent thought it didn’t and seven percent didn’t know or were neutral.

* 88 percent of Republicans also termed themselves “pro-Israel,” a label that only 46 percent applied that label to themselves.

* Most important for those looking to handicap a vote on a deal with Iran were those questions relating to support for politicians who are perceived as friendly or hostile to Israel. Only 18 percent of Democrats said they would be more likely to vote for a politician who defended Israel’s right to self-defense while 76 percent of Republicans said they would. 32 percent of Democrats and only seven percent of Republicans said they would be less likely to back such a politician. On the other hand, 45 percent of Democrats and only 6 percent of Republicans said they would be more likely to vote for a politician who criticized Israel. 75 percent of Republicans and only 23 percent of Democrats said they would be less likely to vote for such a politician.

* For those looking for a link to anti-Semitism, while a majority of both parties saw anti-Semitism as a problem in the United States, fully 50 percent of Democrats but only 18 percent of Republicans agreed with the proposition that, “Jewish people are too hyper-sensitive and too often label legitimate criticisms of Israel as an anti-Semitic attack.”

This data confirms what has already become obvious. While clear majorities of both parties in Congress are part of a strong pro-Israel coalition, support for that consensus among rank and file Democrats is weak and growing weaker all that time. That means Democrats inclined to choose partisan loyalty to Obama over support for Israel’s survival face fewer critics within their party. Where a Republican inclined to throw Israel under the bus would face a wall of opposition from his party, Democrats may have no such fears.

Though the agreement the president will present to Congress will almost certainly fall short of the same criteria that the administration presented before the negotiations began, the soft support for Israel among Democrats will be Obama’s trump card as he twists arms and hands out favors in search of Democratic votes to sustain a veto of the Iran deal. This means the debate on Iran will not be so much one about policy as a battle for the soul of a Democratic Party that has lost its way on Israel.

Some will blame this state of affairs on the Israeli government or even Republicans for “politicizing” support for the Jewish state. But such arguments are entirely disingenuous. The fault here lies entirely with Obama and the left-wing of the Democrats who have embraced positions attacking Israel and, in the case of Iran, prioritized détente with the Islamist regime over support for America’s only democratic ally in the Middle East.

It is true, as I wrote earlier this year, that both Republicans and Democrats failed when they passed the lamentable Corker-Cardin bill that created an approval procedure for the Iran deal that turned the treaty confirmation process on its head. The president should have been forced to present the agreement as a treaty that requires two thirds of the Senate to vote yes for it to be ratified. Instead, distracted by Obama’s disingenuous designation of the deal and bullied by the president’s rhetoric, they voted for a bill that allows it to become law with only the one-third plus one of one of the two Houses of Congress to sustain a veto.

But any chance to vote on the most important foreign treaty in a generation should have caused both the Republican and Democratic caucuses to stand firm on an issue on which there has always been a clear consensus. Unfortunately, that hasn’t happened despite obvious evidence that the president has decided any Iran deal, even an indefensible one, is better than none at all. If Obama succeeds in getting his Iran deal, and the odds favor it, blame Democrats for abandoning their pro-Israel principles, not Republicans or the Israelis.