For now, Iran’s nuclear program appears to be curbed—at least in the sense that negotiators in Vienna have finally announced a deal. (Although even the most optimistic must bat an eye when they remember that the U.S. Senate still has to approve the terms.) Meanwhile, the most pessimistic are still worried: Can the deal actually prevent Iran from acquiring a bomb? And how would the power balance in the Gulf be upended if it it did not?

The prospect of a resurging Iran—nuclear or otherwise—is dangerous, but not for the reasons often cited. For example, the fears that a nuclear Iran would result in a Middle Eastern proliferation cascade are exaggerated. There are only two countries even somewhat likely to respond to a nuclear Iran in kind: Israel, which already has a nuclear capability, and Saudi Arabia, which could potentially have plans to build—or buy—its own weapons. (The most-likely course is for Saudi Arabia to purchase a readymade bomb from Pakistan, or possibly North Korea.)

Regardless, even if the Saudis want nuclear weapons, they don’t need them. Even in a world with a truly nuclear Iran, they would win in an all-out conflict without them. And they probably know well that the path to nuclear weapons is long, costly, and painful—in essence, not worth it.

First, Iran wouldn’t use the bomb in a conflict if it had it: it won’t have an incentive to use its nuclear weapons aggressively, and the weapons themselves may not even change its foreign policy. Indeed, dissenting voices like the late Kenneth Waltz actually supported a nuclear Iran, arguing that it would insert an element of systemic stability in the Middle East.

While Iran might be able to take out a few key targets using its few, hypothetical nuclear weapons, doing so would serve no strategic purpose. Other nuclear states would be forced to respond, making it clear to Iran that the consequences for nuclear use would not be anything less than existential. Some have nevertheless argued that Iran could resort to the nuclear option against key adversaries like Saudi Arabia or Israel, despite the risk that doing so would have for Iran’s own survival. Such arguments are based on false assumptions about Iran—instead, as Annie Samuel writes, “The Islamic Republic is not an irrational or suicidal regime. A nuclear weapon will not make it one.”  

If the conflict won’t go nuclear—and it won’t—then all Saudi Arabia has to worry about is that the acquisition of a bomb would embolden Iran’s bellicosity. Even so, Saudi Arabia has enough conventional dominance to console any such fears. On the conventional side, it is a numbers game. Saudi Arabia outspends Iran 5:1. A full 25 percent of the Saudi budget is committed to military spending, amounting to more than $80 billion in 2014 alone. When Saudi Arabia’s Gulf allies are factored into the equation, Iran looks even shabbier: the Gulf Cooperation Council (GCC) states together spend thirteen times Tehran’s military budget.

Saudi Arabia doesn’t just have more weapons, it also has better ones. Russia, China, and Ukraine are the only countries Iran has imported arms from since the mid-1990s, and even they have shown considerable restraint in their willingness to sell to Iran. As a result, Iran’s military often finds itself “relying on systems originally delivered at the time of the Shah, or lower grade imports, many of which reflect the technologies of the 1960s to 1980s.” The new deal with Iran won’t change this. Parts of the arms embargo remain in place, meaning it will still be difficult for Iran to scale up its military equipment. Even without the embargo, however, the windwall from sanctions relief would have gone to addressing Iran’s pressing domestic needs, like crumbling infrastructure, rather than to a defense spending spree or to Shiite militias abroad.

In the meantime, the West has been lavishing the GCC states with military aid and arms transfer agreements—at a total value of more than $90 billion to Saudi Arabia alone over the last five years. Iran’s defense technology is mostly ineffective against the Gulf’s cutting-edge arsenal. Even Tehran’s prized Hormuz missiles won’t “be terribly effective against modern air-defense systems such as the U.S. Patriot,” which have already been disseminated throughout the Middle East.

In a practical sense, Iran and Saudi Arabia don’t share a border, so in any attack, Iran would have to go through Iraq or Kuwait. Either path would likely embroil the militarily superior United States, which has troops in both places. Current U.S. security guarantees to Saudi Arabia suggest that, even if Iran managed to avoid tangling with American troops before reaching the Saudi border, the United States would still likely get involved.

The overarching threat in the Gulf is not a proliferation cascade nor a direct conflict with the Saudis—it’s Iran’s potential ability to limit the United States’ power-projection. One such theater is the Strait of Hormuz, a chokepoint of the global energy flow and a centerpiece of U.S. Gulf strategy. Although tensions there have existed since the issuance of the Carter Doctrine in 1980, Iranian belligerence in the Strait of Hormuz is more of a worry than a problem: so far, Iran’s strategy in the Strait has been to occasionally nuisance the United States, only to back down before making it truly mad, not to engage in a grand challenge to U.S. force-projection. The threat of angering the United States itself is a deterrent, which current conditions in the Strait actually show.

Combativeness there has slowed down recently, an act that can be traced to Iran’s current need for cooperation with the United States. Iran knows, then, that aggressiveness in the area is a dangerous move—and in a high-stakes military situation, which a nuclear Iran would necessarily bring, such a risk simply wouldn’t be worth it. After all, a disruption of the traffic in and out of the Strait is as risky for Iran as it is for the United States: Iran’s valuable oil exports require that pathway.

There’s little reason for the Strait of Hormuz to ever become a conflict flash point. And nuclear weapons won’t change that, since they will not fundamentally alter Iran’s policies. They are not a panacea that will upend the general strategic dynamics in Iran’s favor. If anything, nuclear weapons would dramatically constrain Iran’s room for maneuvering, since reneging on the Vienna deal would reduce Iran to a diplomatic pariah and mobilize the international community against it.

Even today, Iran is already overstretched in terms of both funding and military resources—it has no incentive to provoke yet another fight. No matter the strategic relevance of its current wars in Iraq, Syria, Lebanon, and Yemen, Iran cannot indefinitely sustain its adventures abroad. And, to put it mildly, none of its current fights will be easy wins to start with. In sum, Iran is simply outgunned, outspent, outflanked, and overstretched. Deal or no deal, nuclear weapons or none, there are only two outcomes: either Iran makes the smart choice, and avoids conflict, or it loses to the Saudis and their American allies.

Selim Can Sazak, an intern at The Century Foundation is a Fulbright scholar from Turkey studying at Columbia University’s School of International and Public Affairs. Lauren R. Sukin is a Publications Intern at The Century Foundation.

Image: Office of Iran's Supreme Leader