For at least a decade, when asked during meetings with government representatives about priority concerns, I have typically listed them as: “Iran, Iran and… Iran.”

No one country is, to be sure, the be-all and end-all of the world’s problems, or the Middle East’s. But Iran – by far the strongest and most vociferous state adversary of Israel – is the patron of most of the non-state forces committed to terrorizing Israel’s people. In fact, both its clerical leadership and its proxies are doctrinally committed to preventing peace with the Jewish state – and to that lone regional democracy’s very destruction.

However, the deadly menace posed by Iran far surpasses even this. The United States, whose own “death” Iranian regime-incited crowds continued to urge even during the recent diplomatic engagement, has long recognized Iran as the leading state sponsor of global terrorism, with casualties spanning from Argentina to Bulgaria. Of late, much alarm has rightly been raised over the horrors of the so-called Islamic State (a Sunni group), but too many have become indifferent to the horrors, domestic and otherwise, of the (Shi’ite) Islamic Republic. In addition to the notorious Quds Force of the regime’s Islamic Revolutionary Guard Corps, a key, fragile Mediterranean country, Lebanon, is politically dominated by Iran-sponsored Hezbollah – the foremost military power at home, long the “A-team of terrorists” on the international scene, and the defender of last resort of its allied Assad regime in Syria, whose civil strife has seen far more Arabs killed in only four years than have been in at least 70 years of the conflict involving Israel. Indeed, in virtually every site of severe violence and turmoil in the region, from Iraq to Yemen – where dramatically emboldened Houthi rebels now openly hawk their mantra of “God is Great, Death to America, Death to Israel, Damnation to the Jews, Victory to Islam” – Iranian fingerprints are to be not-so-subtly found.

Little wonder, then, that for all the chatter in Washington about Israeli Prime Minister Netanyahu’s “hard-line” demands and anxieties on Iran, those same sentiments are matched, at the very least, by virtually all of America’s Arab partners as well – those who know Iran best and must live with it as next-door neighbors. Notably, no action and no capacity on the part of Israel, and no sharp political differences that they have had with it, has ever so alarmed the Arab states as a potentially nuclear-armed Iran has. Presaging a nuclear arms race in a region that can least afford it, and during an American presidency that had aimed for global nuclear non-proliferation, those Arab states have pledged to match any military capacity that the Iranians acquire.

Little wonder, then, that Israelis across party lines – already facing the most brutally inhospitable of neighborhoods – have been so extraordinarily adamant that the most dangerous of governments not have any capability to obtain the most dangerous of weaponry.

And “capability,” to be certain, is what is key; the watering down of fundamental benchmarks for a nuclear agreement with Iran – from “no nuclear-weapons capability” to “no nuclear weapons” – was a significant, early blunder by international negotiators. Those negotiators have now managed to reach a hard-won deal with Iran – notwithstanding unceasing public animosity, and relentless re-interpretation of mutual understandings, on the part of supreme Iranian authorities – and that deal may buy some short-term benefits. The question is, do temporary benefits outweigh lasting hazards and damage? Fully assessing the agreement’s benefits and drawbacks may be possible only over the course of months, if not years.

Filling a vacuum of uncertainly, the Iran deal could wrest transient Iranian restraint in its nuclear activities for the first time in years, and at a time when world powers, facing an Iran whose nuclear program is now extensive, have either been complicit in or unsure about how to contend with that advancing program. But, by virtually all accounts, Iran has been allowed to remain a nuclear-threshold state, with much of its nuclear infrastructure (and some of its nuclear research and development work) remaining intact. As critically, after only ten or fifteen years of the agreement’s duration, Iran would be significantly freed to race for a nuclear bomb – with world powers left in the same position of determining how, if at all, they might obstruct this unprecedented disaster for international peace and security. Meanwhile, the economic sanctions that at least strained Iranian mischief-making endeavors and prompted the Iranians to negotiate will have been lifted (with just limited possibility of effective restoration). Iranian pursuit of conventional but ever-more-lethal arms will also have progressed unabated – indeed now likely escalated, with foreign acquiescence – and Iran’s de facto status as a nuclear player will have been conceded to by its heavyweight interlocutors.

Even without these factors, cynics – or, as they might prefer, realists – have good reason to fear that the landmark agreement with Iran will not yield responsible Iranian policies or movement toward regional stability. A much-heralded political agreement, and international inspections, utterly failed to stop even singularly isolated North Korea from becoming a regime possessing nuclear weapons. And we know one thing about Iran: notwithstanding its supreme leaders’ express disavowal, in religious terms, of obtaining nuclear arms, Iran has practiced incessant duplicity and subterfuge in its stunningly aggressive pursuit of nuclear capabilities – a pursuit that the world’s most well-informed intelligence agencies unmistakably recognize as consistent with a hunt for access to the most dangerous weapons in existence. The very ability to “break out” as a nuclear-armed state and state-sponsor of terrorists may, after all, be all that Iran needs to afford itself and its proxies relative impunity for their violent fanaticism – or a safeguard against any external notion of supporting Arab Spring-style uprising in Iran, like the abortive one of 2009. The very inability of the U.S. to prevent the unthinkable but long-anticipated would certainly prove a victory for the Islamic Republic – and an undermining of confidence in Washington’s preparedness to defend core interests and allies.

The hope of those endorsing the international nuclear agreement with Iran, beyond interest in again freeing up Iranian oil resources and business opportunities, may not rest on expectation of organic Iranian regime or policy change as much as a mix of trust in an active (if decidedly constrained) inspections protocol, optimism that valuable time will have been bought to detect and effectively disrupt any Iranian nuclear misdeeds, and suspicion that Iranian domestic political considerations (particularly demands for sanctions relief) will ultimately outweigh the temptations of a wild nuclear adventurism. But Iran’s nuclear campaign, despite all the outside pressures and scrutiny, has proven tellingly determined. The policy calculus of an ideologically radical theocracy like Iran, after all, may well differ from the mundane considerations of politicians in foreign capitals like London, Paris and Vienna. Moreover, with the mullahs’ many hard-earned foes, a nuclear “deterrent” may not take a back seat in Tehran to economic growth and rising employment rates as a perceived necessity for self-preservation and policy advancement. If Iran does reach a point of no return in its ability to acquire nuclear arms, the country might even eventually be able to have its cake and eat it too – enjoying near-hegemony in its neighborhood as well as economic strength, enabled by an international community hungry for oil and wary of war.

The war-wariness of Westerners and others is, of course, understandable, and the new deal with Iran does seem poised to make irrelevant the already tepid threat of a Western military response to Tehran’s nuclear activity. No doubt, a military confrontation with Iran – already such a destructive force on the international scene – would have been terribly costly. The only thing far more costly is the prospect of confrontation with an Iran whose illicit nuclear ambitions have been allowed to come to fruition.