Arms embargos are often dismissed as symbolic, and therefore ineffective. But just because something is symbolic, doesn’t mean that it won’t have an effect. A U.S. arms embargo against Saudi Arabia would be a clear signal of American disproval of Saudi actions in Yemen, and would be an equally important signal to Washington’s allies, who are left wondering if the United States is ambivalent or uninterested in the growing Yemeni humanitarian catastrophe.

By continuing to provide weapons, President Donald Trump tacitly endorses Saudi policies. This signal is strengthened by Trump’s recent veto of the resolution that called for an end to U.S. support for the war in Yemen. While Trump justified the veto by saying that the resolution was a “dangerous attempt to weaken my constitutional authorities,” statements from Congressional representatives show they are aware of the powerful signals sent by arms sales. Sen. Tim Kaine said that the veto “shows the world [Trump] is determined to keep aiding a Saudi-backed war that has killed thousands of civilians and pushed millions more to the brink of starvation.” An arms embargo against Saudi Arabia would be a signal both to leaders of that country, and other states, that the United States does not endorse Saudi actions. Those arguing against a ban are correct on one point: Embargos as blunt force instruments of coercion are rarely effective. But arms embargos are effective as signals of political dissatisfaction, and serve an important communication role in international politics.

Arms Embargos Are Signals and Can Build Coalitions

Policymakers and scholars agree that arms embargoes are not effective “sticks” in international politics. Rarely do states cave when faced with punishment in the form of an embargo. But even if an arms embargo isn’t a direct tool of coercion, an embargo would be an important political signal. There are at least two reasons for the United States to seriously consider an arms embargo against Saudi Arabia.

First, arms sales are signals that cut through the noise of the international system. Cutting off arms transfers is a common way that states express their dissatisfaction with others and try to influence behavior. As Lawrence Freedman observed in 1978, “refusing to sell arms is a major political act. It appears as a calculated insult, reflecting on the stability, trust, and credit-worthiness, or technical competence of the would-be recipient.” Yet this crucial point seems to have been lost in the current policy debate about whether or not the United States should continue selling arms to Saudi Arabia. My research shows that stopping arms transfers or denying requests is an effective way to signal dissatisfaction and causes the would-be recipient to re-think their behavior.

Take, for example, the U.S. relationship with Israel in the 1960s. The United States sold Israel Hawk surface-to-surface missiles in 1962, M-48 Patton tanks in 1964 and 1965, and A-4E Skyhawk bombers in 1966. Israeli leaders understood that these transfers signaled a close U.S.-Israeli relationship. As diplomat Abba Eban wrote, the arms transfers were “a development of tremendous political value.” Even against this backdrop of close ties and significant arms sales, Israeli leaders were extremely sensitive to arms transfer denials. In April and May 1967, the United States denied Israeli requests for armored personnel carriers and fighter jets. Approving the transfers would have signaled support, and likely emboldened Israel, as tensions were growing in the region. Israeli leaders believed these transfer denials overruled prior signals and demonstrated that the United States was not willing to be a close political ally for Israel. Eban described Israel as “isolated,” and the head of Israel’s intelligence service said that the arms transfer denials made it clear that “in Israel, there existed certain misperceptions [about the United States].” If arms transfer denials could have such a significant effect on Israeli thinking — keeping in mind that there was a close and significant political relationship between the US and Israel — imagine what a transfer denial would mean for U.S.-Saudi relations. Like Israel, Saudi Arabia would have to re-think its impression that it has political support and approval from the United States. We can, and should, ask whether or not withdrawal of U.S. support would affect Saudi behavior, but it’s important that this question not get overlooked in the current debate.

Because arms transfers (and denials) are powerful signals, they can have an effect even before a transfer is actually completed. This suggests that even the announcement of an embargo against Saudi Arabia could have an effect. Take, for example, Taiwan’s recent request for a fleet of new fighter jets. As reports mounted that Trump had given “tacit approval” to a deal for F-16 jets, China’s protests increased. The United States has not sold advanced fighter jets to Taiwan since 1992, partially out of fear of angering China, which views Taiwan as a renegade province. Even if the deal for F-16s is formally approved, Taiwan is unlikely to see the jets until at least 2021, and the balance of power between China and Taiwan would not change. As one researcher observed, the sale would be a “huge shock” for Beijing, “But it would be more of a political shock than a military shock. It would be, ‘Oh, the U.S. doesn’t care how we feel.’ It would be more of a symbolic or emotional issue.” Yet China’s immediate, negative reaction to even the announcement of a potential deal shows how powerful arms transfer signals can be.

If this same logic is applied to an arms embargo against Saudi Arabia, an arms embargo would signal that Saudi Arabia does not have the support of the United States. This signal would be an important first step in changing Saudi behavior because it would override other statements and actions the United States has sent that indicate support. And Trump has given Saudi Arabia a number of positive signals: He called Saudi Arabia a “great ally” and dismissed reports that that the Saudi government was involved in the murder of journalist Jamal Khashoggi. He has expressed interested in selling nuclear power plants and technology to Saudi Arabia. And he has repeatedly claimed that he has made a $110 billion arms deal with Saudi Arabia (he hasn’t). With these clear signals of support, why should Saudi Arabia alter its behavior based on resolutions that come out of the House or Senate, which are likely to be vetoed by Trump, anyway? An arms embargo would be a clear and unambiguous signal that the United States disproves of Saudi actions in Yemen.

The second reason for supporting an embargo concerns U.S. allies and the logistical difficulties of making an embargo have an effect. One of the reasons embargoes have little material impact is because they require cooperation among weapons exporting states. A ban on sales from one country will have little effect if the target of the embargo can seek arms elsewhere. Germany, instituted an arms ban against Riyadh in November 2018, and German leaders have pressured other European states to stop selling arms to the Saudis. Germany understands the importance of the embargo as a political signal: as a representative of the German Green Party explained, “The re-start of arms exports to Saudi Arabia would be a fatal foreign policy signal and would contribute to the continued destabilization of the Middle East.” But the German embargo has had minimal effect because Saudi Arabia can get arms elsewhere.

According to the 2019 Military Balance, most of Saudi Arabia’s equipment is American or French in origin, such as the M1A2 Abrams and AMX-30 tanks, Apache and Dauphin helicopters, and F-15C/D fighter jets. Saudi Arabia has some equipment manufactured wholly or in part in Germany, such as the Eurofighter Typhoon and the Tornado ground attack craft, but these weapons are a small portion of its complete arsenal. A U.S. embargo would send an important signal to the allies who also supply Saudi Arabia, allowing them to explain participation in the embargo to their own domestic constituencies. This is especially important for countries like France, Germany, and the United Kingdom, that need to export arms to keep their own production lines running. While the research shows that sustaining an arms embargo is often the most difficult step, embargoes can restrain sending states’ arms exports. Even if a U.S. embargo won’t have a direct effect on Saudi Arabia on its own, an embargo is important for building coalitions for a more expansive embargo that could affect Saudi behavior.

The Difficulty of Stopping Atrocities

Beyond signaling, we know U.S. arms sales often end up in the wrong hands, and have been used in Yemen. The Saudi-led war in Yemen has led to starvation conditions, caused thousands of civilian casualties, and has led to the displacement of millions of people. The United Nations estimates that 80 percent of Yemen’s population – 24 million people – require some form of humanitarian or protection assistance, and that the severity of the situation is increasing. Would an arms embargo create meaningful change in Yemen?

An initial effect of an embargo is that Saudi Arabia would have to work harder to access war materiel. As Jonathan Caverley noted, more than 60 percent of Saudi Arabia’s arms delivered in the past five years came from the United States. Even if this percentage decreases over time, it will be costly for Saudi Arabia to transition to a primarily Russian- or Chinese-supplied military. Though Saudi Arabia might be willing to pay this cost, it would still have to pay, and take the time to transition to its new weapons systems. This would represent a brief break in hostilities that could facilitate the delivery of aid and assistance in Yemen.

The United States could, in theory, impose stricter end-user controls on Saudi Arabia. This would have the advantage of keeping Saudi Arabia within the world of U.S. weapons systems, and might prevent it from diversifying its suppliers, which would ultimately weaken any leverage the United States might have. Longer-term, it would not be to America’s advantage if Saudi Arabia takes a lesson from Turkey, and starts courting Russia as a new arms supplier. It is difficult to enforce end-user controls, since, once a weapon is transferred, the recipient can use it however it wishes. It might also be the case that Saudi Arabia would object to stricter end-user controls, and would seek new suppliers as a result.

An arms embargo will not be a panacea. But not doing something sets a problematic precedent, and allows the difficulty of coordinating an arms embargo outweigh the potential benefits of one. An embargo is unlikely to have an immediate effect on Saudi behavior, because an embargo would be a political signal, rather than a blunt instrument of coercion. It will take time for a multilateral embargo to emerge and be put into place, and the United States should work with its allies to help support their ability to participate in the embargo. Not acting, however, would continue to implicitly endorse Saudi behavior, and would make it more difficult for U.S. allies to believe that future threats of an embargo are credible.

Jennifer Spindel is an assistant professor of international security at the University of Oklahoma, and the Associate Director of the Cyber Governance and Policy Center. You can follow her on Twitter: @jsspindel

Image: Ahmed Farwan