An air of unreality pervades much of the debate on the agreement to restrict Iran's nuclear program. Opponents of the agreement raise issue after issue on which the agreement is clearly superior to the alternative that would exist if the opponents succeed in getting the U.S. Congress to kill the deal, but the opponents keep raising such issues anyway. There is, for example, long discussion of the details of inspection arrangements and exactly how many days will elapse between when an accusation is made and when international inspectors could enter a facility. But to the extent any of this is intended as criticism of the agreement it is beside the point because if the agreement is disapproved there would not be any such extraordinary inspections, with 24 days or 240 days or anything else in the way of an adjudication period. Indeed, if the agreement is killed the universe of possible Iranian “violations” of its obligations would be greatly shrunk because Iran would be under no restrictions at all regarding its nuclear program other than the basic commitment under the Nuclear Nonproliferation Treaty not to build weapons. Similarly, complaints about the number of years certain limits on the Iranian program will be in effect are beside the point because if the agreement is killed there will be zero years of limits.

Everything that has been gained under this agreement in the way of restrictions on, and monitoring of, the Iranian nuclear program is a net, as well as a gross, gain over the situation that prevailed before the negotiations began and over the situation that would prevail if the agreement is killed. To get these gains, neither the United States nor its negotiating partners nor Iran's regional rivals have had to give up anything that involves any significant risks to themselves. As former International Atomic Energy Agency chief Hans Blix has put it, in return for all the far-reaching commitments Iran has made, the only commitment our side has had to make is to “drop punishment”.

If the current debate were being conducted solely on the merits of the agreement, the outcome would be almost a no-brainer; the agreement is obviously much better than the alternative of killing the agreement, even on a litany of issues that the opponents themselves have been raising. And yet the agreement's political fate on Capitol Hill does not reflect that. There is substantial probability that Congress will pass a resolution of disapproval—an action that, if allowed to stand, would kill the agreement. There is a lesser, but still significant, chance that Congress would override a presidential veto of such a resolution. The final outcome is likely to come down to the votes of only a few senators or representatives. None of this political prognosis is understandable if one focuses on the substance of the agreement itself. The prognosis is comprehensible only if one realizes that the opposition is being driven by other reasons some people have for wanting to kill this agreement and to preclude any agreement with Iran.

The forces at play will be easily understood and written about by future generations of political scientists. But the American public and politicians are being buffeted (or swept along) by those forces right now. It behooves us to recognize explicitly the principal ones responsible for opposition to this agreement, which are the following.

The Israeli government's political stratagem. Even the most fervent Israel-lobby-denier cannot deny that the Netanyahu government is leading the charge against the agreement at least as much as anyone else is leading it. In Israel, as in the United States, there is a disconnect between sober consideration of the substance of the agreement and other political incentives that are making that kind of sober consideration difficult. Significant and understandable concern exists across the Israeli political spectrum about any possibility of an Iranian nuclear weapon. It makes sense, from the standpoint of security of the State of Israel, to support an agreement that restricts and scrutinizes Iran's nuclear program and not to favor killing such an agreement and thereby removing such restrictions. That is why many leading Israeli security professionals, who have dedicated careers to the safety and well-being of their nation, have, even while holding their noses over any dealings with the Islamic Republic of Iran, concluded that the agreement is in Israel's best interests. If Prime Minister Netanyahu were focusing chiefly and carefully on ensuring there will be no Iranian nuclear weapon, he would have announced the same conclusion. Clearly he has other motivations.

Netanyahu has come to center much of his political career on fearmongering about Iran. In addition to however this tactic works in his favor against domestic political opponents, with his posturing as a tough guy who stands up to foreign threats, endless enmity with an Iran that is endlessly treated as a rogue state serves other purposes for his government. Keeping Iran in an international penalty box lessens the competition for influence from a regime that will continue (certainly as long as the Palestinian issue remains unresolved) its extremely harsh criticism of Israeli policy. The Iranians may be no more irate about those policies than are the governments of the Gulf Arab states, but Iran is not as restrained in its rhetoric as the latter governments are because of their relationship with the United States.

Emphasizing an overriding threat from Iran, as Netanyahu does in any statement or speech about foreign affairs, also serves as a major rationale for continuation of the extraordinary U.S.-Israeli relationship and for framing Middle Eastern affairs in the moderates-vs.-bad-guys-led-by-Iran framework that Netanyahu's government prefers. Undermining any incipient rapprochement between the United States and Iran helps to sustain the notion that Israel is the only reliable partner for the United States in accomplishing anything important in the Middle East. Last but not least, repeatedly invoking Iran as the “real threat” in the Middle East serves to divert attention and change the subject whenever people start to talk about things, such as the occupation of Palestinian territory, that Netanyahu's government would rather not talk about.

Netanyahu surely does not want to see an Iranian nuclear weapon, but his own behavior and positions indicate that neither does he want to see the issue of Iran's nuclear program resolved. It serves his purposes to let the issue fester indefinitely, and to have tension with Iran continue indefinitely. To the extent that the new agreement does resolve the nuclear issue—and even worse from Netanyahu's point of view, to the extent it leads to the United States and Iran doing worthwhile business on other topics—all of the aforementioned advantages to him of endless enmity with, and endless rogue status for, Iran are undermined. And so he is doing everything he can to kill the agreement even though the agreement is in Israel's broader and longer-term interests.

Thus there are the rhetorical excesses such as endless fulminations about repeating Munich. There are Netanyahu's repeated warnings, which he has been making for many years even though they keep getting disproved, that Iran is just a few months away from having a nuclear weapon. There is plenty of other inconsistency and goalpost-shifting, as in presenting his cartoon bomb to the United Nations and then not saying anything more about it after an agreement was negotiated that drained his bomb, or in first denouncing the Joint Plan of Action of November 2013 and then backing off when he was denouncing a later and more comprehensive agreement. Consistency doesn't matter to him; what matters is throwing sand into the gears of U.S. diplomacy.

As always in American politics, when the Israeli government takes this unequivocal a position on something, its lobby springs into action. And so AIPAC is making a huge, cancel-staff-vacations effort to destroy the agreement. Although even AIPAC sometimes has had its own frustrations with the Netanyahu government when the latter has put a highly partisan slant on its interference in U.S. politics, the lobbying organization has its own institutional reasons to continue to beat the drum of Iran as an everlasting threat. An anonymous former AIPAC official comments, “Iran has been the group’s raison d’être for two decades and it doesn’t know what else to do; its troops are trained to attack Iran and the lobby can’t afford to admit failure lest it lose supporters.” The former official continues, “Iran has been an enormously lucrative fundraiser for AIPAC; just look at what they’re spending on this campaign alone. It needs to keep the issue alive for institutional imperatives.”

Partisanship. As conspicuous as the Israeli government's role in the campaign to kill the Iran agreement is the partisan divide in the United States. That divide is immediately apparent in the most recent hearings on the subject, as it has been all along with other Congressional action or attempted action to sabotage the negotiations, such as proposals for new sanctions that would have violated the Joint Plan of Action and torpedoed the whole process. There is nothing in declared Republican Party principles, such as support for free markets, low taxes, and a strong national defense, that explains opposition to the agreement. Nor does any determination to oppose resolutely any possibility of an Iranian nuclear weapon explain the opposition when killing the agreement would mean lifting restrictions under which the Iranian nuclear program currently operates. A more plausible explanation for Republican opposition against the agreement is that it is a major initiative of Barack Obama.

The role of anti-Obamaism in Republican positions has been illustrated by the party's obsessive opposition to the Affordable Care Act, with the dozens of time-wasting repeal votes in Congress and refusal to countenance any acceptance of the act or constructive bipartisan tinkering with it, even though it uses a commercially-based formula that was Romneycare in Massachusetts before it became Obamacare. The ACA is widely regarded as President Obama's biggest single accomplishment in domestic affairs, and the nuclear agreement with Iran is widely regarded as what will be—if it is not killed—his single biggest achievement in foreign affairs. Thus the agreement excites the same partisan impulses and the same urge to kill, no matter what the consequences that killing would have on the subject it addresses. The reflexive, unthinking nature of what flows from those impulses was illustrated by how quickly a large majority of Republican senators (probably to the later regret of many of them) signed on to the atrocious open letter to the Iranians initiated by Tom Cotton, a freshman with less than two months on the job.

Once such a partisan pattern develops, it becomes, as with so many other questions both factual and prescriptive, a guide for party faithful in determining their own opinions. The partisan divide in the public's views of the Iran agreement as recorded in opinion polls reflects to a large extent individual citizens' taking of cues from leaders of the party with which they identify. The self-reinforcing nature of Republican hostility to the agreement has been reinforced further by the contest for the Republican presidential nomination, in which a platoon of contenders has to scramble to get enough attention from the party base just to make it onto a debate platform, and in which a candidate opens himself up for attack just by suggesting that it might not be prudent to demolish on one's first day in office an agreement that had been already working for a couple of years.

The Iran nuclear issue is by no means the first major national security issue in recent years in which careful consideration of what is best for national interests is superseded by reflexive partisanship. Peter Beinart notes significant parallels between the debate (or what passed for debate) on launching the war in Iraq and current debate about the Iran agreement, including how many of the same people who were the most enthusiastic supporters of that blunder of a war are among the most vocal opponents of this agreement. Another parallel, which Beinart does not go into in his piece, concerns how party politics played into each question. With Iraq when Congress voted on a war resolution in 2002, as with Iran today, most of the key swing votes were Democrats. The Democrats in 2002 faced a political hazard if they appeared to resist the post-9/11 tidal wave of American militancy that the war promoters exploited to muster support for their project. That hazard was great enough that the war resolution gained support from a majority of Democrats in the Senate (where most of the party's presidential hopefuls were to be found), though not from most Democrats in the House of Representatives. But the biggest support by far in both chambers came from the nearly unanimous yes votes of Republicans.

Michael Isikoff and David Corn in their book Hubris give an insight into some of the thinking among those Republicans with a quotation from Texas Republican Richard Armey, who was the majority leader in the House at the time. Armey had earlier expressed reservations about starting a war in Iraq. When he and other Congressional leaders received a pro-war briefing, complete with overhead imagery, from Vice President Dick Cheney, Armey was unimpressed. “If I'd gotten the same briefing from President Clinton or Al Gore I probably would have said, 'Ah, b***s***',” recalled Armey. But, he continued, “You don't do that to your own people.” Given the substantive choice between the Iran agreement and killing the agreement and what each of those alternatives would mean for restricting and monitoring the Iranian program, perhaps there are similar private thoughts among some Congressional Republicans today as they listen to arguments that opponents are firing at the agreement. And probably for most of those members party solidarity will again prevail.

Anti-Iran xenophobia. The Islamic Republic of Iran has come to fill, almost from the start of its existence but certainly since the end of the Cold War and the collapse of the USSR, the role of chief bête noire in American minds as far as foreign countries are concerned (although lately Vladimir Putin's Russia has been making a bit of a comeback in that regard). The hostage crisis of 1979-1981 was the worst possible way to get off to a start with a new regime. American emotions and attitudes about Iran have never recovered, and they certainly have not kept pace with major evolution in the Islamic Republic's own attitudes and objectives, which long ago became post-revolutionary in nearly every sense of the term. Put simply, most Americans have a visceral dislike of Iran that leads the emotional to dominate the intellectual, that colors perceptions and fuels major misperceptions of what Iran is up to, and that caters to the most primitive and most negative depictions of the country's regime and its objectives.

Anyone who made a sober and rational appraisal of the alternatives of agreement and no agreement as far as the Iranian nuclear program is concerned could still, no matter how much he or she dislikes Iran, see the wisdom of the agreement. As the administration has repeatedly and truthfully noted, this is an agreement based on distrust, not trust. And as many others have correctly noted, some of the most important agreements one makes are with one's enemies, not one's friends. But in reality, emotionalism and bias often trump sobriety and rationality, as they have to a large degree in this case. The American public's feelings in this regard provide a fertile ground on which those who, for the reasons mentioned earlier, are determined to oppose the agreement can plant mistaken beliefs and can stir up still more negative emotion.

The anti-Iran sentiment affects the debate in several specific ways. The consistent worst-casing of Iranian objectives and intentions leads to many misperceptions because often the worst-case assumption is simply incorrect. (E.g., Iranian leaders are not really out to destroy Israel, and they are smart enough to realize there would be no way for them to do so even if they wanted to.) Clichés and sloppy formulations substitute for any careful examination of what Iran actually has and has not been doing (a problem especially apparent concerning Iran's activities in the Middle East). The regarding of anything Iran does as being by definition “nefarious” overlooks how Iranian actions relate to U.S. interests, sometimes complementing and sometimes conflicting with them. The assumption that Iranian intentions are uniformly malevolent and always will be malevolent leads to gross misunderstanding of actual Iranian intentions, how those intentions underlie what has already happened in the nuclear negotiations, and how intentions and not just capabilities are a major part of the agreement succeeding in the future. And simple distaste for doing any business with a disliked regime is a further impediment to getting public support no matter how much sense the particular business in question makes.

The Israeli government factor, party politics, and inchoate anti-Iran sentiments are the major reasons an agreement that is clearly in U.S. interests is nonetheless a close call in Congress. Other factors might be mentioned but are subsidiary and less in the nature of root causes than are the aforementioned reasons. Money is one such factor. Copious amounts of it are being spent in opposition to the agreement—far more than anything that can be found on the support side. When the public is largely ignorant about an agreement on a technical subject, money is all the more capable of molding opinions. That effect is in addition to what money that is spent for—and against—re-election campaigns can buy more directly in the way of Congressional votes.

The stakes of the agreement's fate in Congress are high. The most immediate and obvious stake is what Secretary Kerry laid out in his testimony this week: killing this agreement would mean an Iranian nuclear program that would be free of any restrictions and any monitoring other than the minimum to which it is subject under the NPT. Killing the agreement also would mean destroying one of the most significant steps in recent years on behalf of nuclear nonproliferation generally. More broadly and perhaps less obviously, it would mean losing an opportunity to remove a shackle from U.S. diplomacy in the Middle East and to be able to address more effectively and directly many other problems of concern to both the United States and Iran. It would mean damage to U.S. credibility and damage to relations with the European allies who were partners in negotiating the agreement.

Considering the chief reasons for opposition to the agreement brings into focus additional stakes. Killing the agreement would entail a subjugation of U.S. foreign policy to the baleful influences behind the opposition. It would mean a failure to break free of the influence of a foreign government that opposes the agreement for reasons that are not shared interests with the United States and in some respects are directly contrary to those interests (including telling the United States whom it can and cannot do business with). It would mean bowing to the money and the influence of bankrollers such as Sheldon Adelson, who favors dropping a nuclear weapon on Iran and who, although a U.S. citizen, wishes he had performed his military service with a foreign government. It would mean subjugating dispassionate consideration of U.S. national interests to raw party politics. It would mean subjugating it as well to xenophobic bias. None of this is America's better side.

Members of Congress need to think carefully about whether this is the way they want U.S. foreign policy to be made.