In June, the State Department issued a report suggesting that poor oversight over U.S. weapons in the war in Yemen directly led to civilian casualties, starvation, and displacement. On September 7, Senators Bernie Sanders (I‑VT), Elizabeth Warren (D‑MA), and Mike Lee (R‑UT) sent letters in response arguing that the U.S. role in this conflict is “an unacceptable failure” and that the “United States may be complicit to in Yemen would represent a failure in the Biden administration’s stated prioritization of human rights and our core democratic values.”

An estimated 15,000 civilians have been killed in airstrikes carried out by the Saudi-led coalition. Beyond that, the coalition has executed more than 22,000 airstrikes, 33 percent of which struck nonmilitary sites, including schools, factories, and hospitals, according to the Yemen Data Project.

Despite not directly contributing troops to the fighting, the United States has played a pivotal role in the conflict. At least 80 percent of the Saudi pilots who executed these frequent strikes in Yemen received U.S. training. Furthermore, the Kingdom of Saudi Arabia is the United States’ top purchaser of weapons and has been so for the past 10 years. Unfortunately, it has also ranked as one of the riskiest customers of U.S. weapons in every edition of the Cato Institute’s annual Arms Sales Risk Index.

Three successive U.S. administrations contend that weapons sales to Saudi Arabia provide the United States leverage over Riyadh’s policies.

If this is true and leverage exists, there are only two reasons that explain why Saudi Arabia has continued its brutal dictatorship at home and assault on its neighbor despite receiving U.S. weapons.

The first answer is that weapons sales have afforded Washington leverage over Riyadh, but not in visible ways. In other words, the thinking goes, without U.S. support, Saudi Arabia would have behaved more recklessly. If this were true, then there should be no evidence that U.S. support has worsened the situation.

However, the evidence suggests that the United States is empowering Saudi Arabia’s inhumane policies in Yemen. The U.S. military trained Saudi pilots, delivered billions in weapons to Saudi Arabia, and maintained Saudi planes and munitions. It is inconceivable that Saudi Arabia could commit human rights violations to the same level in Yemen without U.S. military support.

From a domestic angle, things are not much better. Crown Prince Mohammed bin Salman rose to power in 2017, becoming its de facto leader. By constantly referring to him as a reformer, the United States has covered up for Saudi Arabia’s inhumane crackdown on women’s rights activists and Shi’ite protestors. If leverage is a dog that does not bark, there is sparse evidence of this being true in the case of Saudi Arabia.

The second argument is that leverage exists in theory but that Washington does not want to use it.

In 1974, during the wake of the Vietnam War and rise of a media covering human rights, then Secretary of State and National Security Adviser Henry Kissinger responded to calls to use leverage against human rights-abusing countries that receive U.S. weapons by saying, “They want us to be anti-Philippine, anti-Korean, anti-Chilean—pro what?” In essence, his argument is that while he theoretically could do something about these countries abusing human rights, the security risk is too great to do so.

Cutting arms sales to Saudi Arabia until they come to a peace agreement with the Houthis would show that the United States wants to use leverage over its weapons recipients. Unfortunately, it is unlikely that policymakers will suggest taking such action, which suggests that this second argument about leverage—however misguided—may have credence.

If neither of these two policies are accurate, though, leverage does not exist. In this case, Washington is approving weapons sales to risky clients on shaky reasoning.

If weapons sales have truly failed to create leverage over Saudi Arabia, then it is a clear example of a failure in U.S. foreign policy, as the human rights situations both in the kingdom and in Yemen have simply gotten worse as they receive more U.S. weapons.

Members of Congress who are questioning Biden’s willingness to continue sending weapons to Saudi Arabia should continue doing so. By pushing for answers on a policy that has historically led to human rights abuses, Congress can push for evidence that weapons sales to risky clients create leverage. It is time to demand answers as to why the United States sells weapons to known human rights abusers under the false pretense that it increases American global power and influence.