Saudi Arabia is threatening, once again, that it will pursue a nuclear capacity to match Iran. It bears mentioning that they’ve done this many times before, and have levied other empty-sounding threats at the U.S. when it is unhappy with American policy. It’s their M.O.

Unfortunately, I’m not as quick to dismiss these latest threats. And it doesn’t necessarily have to do with the Iranian nuclear deal as much as other things happening in the region.

Nuclear parity with regional powers is not a sufficient explanation for any Saudi attempt to move towards nuclear weapons. Israel began developing nuclear weapons 50 years ago, but this never affected the nuclear posture of the Saudis. Saddam Hussein and the Assad family, each at one time rivals to Saudi ambitions, have owned large stocks of weapons of mass destruction—and even pursued nuclear weapons programs covertly—yet the Saudis didn’t budge. Is Iran’s case so different that a nuclear deal with the U.S. would by itself shift Riyadh’s thinking?

Not exactly.

Once again, people are mistaking the symptoms for the disease. To the Saudis, the nuclear deal with Iran is not really about the technical details of what Iran’s breakout time will be. It has a lot more to do with what the Saudis perceive as the nullification of the regional security order—and America’s role in that breakdown.

A radical transformation is under way in Saudi security posture. From the Kingdom’s inception, they have always relied on the protection of outside powers for external security. The Saudi armed forces have served an internal security role, instead.

This arrangement is rooted in the early history of the Saudi state, when Abdulaziz al-Saud led an army of devoted followers known as the Ikhwan to conquer most of the Arabian peninsula in the 1920s. Saud and the Ikhwan came from different tribal regions of Arabia, and when he felt threatened by the Ikhwan’s insubordination in 1927, he drafted fighters from his native Najd region to suppress the Hijazi fighters in the Ikhwan. From that point forward, the regime focused its security resources on domestic security—and left external protection to a great power.

The United Kingdom, with its vast economic interests in the Persian Gulf, initially played that protective role. But the British withdrew from the Gulf in the late 1960s and early 1970s, leaving behind a precarious balance of power between Saudi Arabia, Iraq, and Iran.

The Iranian revolution of 1979 firmly introduced the U.S. as a major Saudi security benefactor, as it forced an end to the hands-off posture of the Nixon Doctrine and brought about the much more assertive Carter Doctrine. From that time, the U.S. has been intimately involved in Gulf security, serving as policeman to protect the Saudis from Iran since the revolution and from Iraq after 1991.

Saudi armed forces participated in very little conventional combat throughout this entire saga. Their lone participation in major military operations—a token presence in the Kuwait liberation forces—was, in the words of Ken Pollack, not inspiring: “Little was asked of the Saudi military during the Gulf War; little was delivered. … At the tactical level, Saudi forces were mostly terrible.” The Saudi military has no defense doctrine, abysmal maintenance practices, lackluster and incomplete training, and overlapping burdens of responsibility. They are a long ways from being a powerful fighting force against a state opponent.

But King Salman has made it clear that the days of Saudi passivity—and deference to the U.S.—are over. The first extraordinary sign of this was the Saudi decision to bomb Houthi positions in Yemen to bolster the pro-government forces—an operation of unprecedented scale for the Saudis. The Royal Saudi Air Force has conducted thousands of sorties in Yemen, pounding Houthi artillery forces and sending errant cluster bombs into civilian neighborhoods. The Saudis are willing to get messy.

Even more alarmingly, reports indicate that Riyadh and Ankara have teamed up to circumvent American policy in Syria. The two countries have decided to back Jaish al-Fatah, a coalition of Islamist forces in Syria that includes the local al Qaeda affiliate, Jhabat al-Nusra. Fed up with implicit American preference for the Assad regime over Sunni Islamists, the Saudis are willing to back a hodgepodge group of extremist militias against Iran’s local ally.

For the United States, what is so troubling about this shift is that certain logical assumptions underpinning Saudi security policy—assumptions that, in turn, were based on the assumption of American protection—are not as safe as they used to be. One of these is the question of atomic weapons.

Even the most informed debate about whether Saudi Arabia would ever “go nuclear” to match a neighboring power has typically lacked insight into the grand strategic level of thinking. The most important question underlying the Iran nuclear issue with Riyadh has not been “Are the Saudis happy with the details of a draft agreement?” but rather, “Are the Saudis happy with American strategy to protect their interests in the wake of an agreement?”

Now that anonymous defense officials are warning that the Saudis have, in principle, an agreement to buy nukes from Pakistan, it’s not as simple as what it was before to dismiss the story as a scare tactic to pressure Washington. It’s time to consider whether there’s some truth in it. The Saudis see a war against Iran unfolding across the Middle East, and it doesn’t trust America to fight it.