Arms sales have been a fixture in American foreign policy since the advent of the Cold War. Selling weapons is a popular strategy in Washington because government officials believe that arms sales provide them a low-risk and flexible tool for reinforcing alliances and containing adversaries while benefiting the US economy. And despite Donald Trump’s skepticism about international trade, it is clear that, at least in this domain, the United States is not about to abandon its role as a global leader. In 2020 alone, the Trump administration has notified Congress of $83.5 billion in potential foreign military sales, while the US was responsible for 36% of the global arms trade between 2015 and 2019.

Presidents talk a lot about supporting allies and creating jobs, but what usually gets ignored is the host of negative consequences that routinely follow. Over the past decade, American weapons have wound up in the hands of the Islamic State and other terrorist groups, been sold on the black market in Yemen and elsewhere, have been used by oppressive governments to kill their own people, and have enabled nations to engage in bloody military conflicts. American arms sales have helped prop up authoritarian regimes, encouraged military adventurism, spurred arms races, and amplified existing conflicts. Since 2002, the United States has sold over $640 billion worth of weapons to 167 different nations, indicating that the United States will sell weapons to almost any nation seeking them.

The dangerous truth, however, is that selling weapons is a very risky business. There is no guarantee that the benefits of any given sale will outweigh the costs. And unfortunately, despite the fact that the Arms Export Control Act requires a risk assessment to be completed before every arms sale, previous research finds little evidence that these sorts of unintended outcomes have any influence on government decisions.

If the United States wants to make sure arms sales are a net positive, the government needs to do a better job assessing the potential risks as well as benefits. To this end, we created the Arms Sales Risk Index in 2018. Running on a scale from 1 (least risky) to 100 (most risky), the index assesses states across six broad factors that the literature identifies as correlates with negative outcomes: corruption, political freedom, state fragility, conflict, state violence, and human rights. In 2020 the average risk score was 40. The three nations with the lowest arms sales risk were New Zealand, Norway, and Luxembourg while the three with the highest risk scores were Syria, South Sudan, and Afghanistan. By ranking and scoring each country in the world along these lines we have built a tool that can help policymakers assess the potential downsides of arms sales more rigorously and efficiently.

The 2020 edition of the index reveals two important new insights. The first is that the American arms sales portfolio has gotten riskier over the past twenty years and that the Trump administration has pursued the riskiest arms sales strategy to date. Part of this stems from decisions made as part of the global war on terror. But more recently, the trend has been exacerbated by new Trump administration policies such as the 2018 update to the Conventional Arms Transfer Policy, which now emphasizes economic benefits as a determining factor in whether to sell weapons abroad. The trend has been compounded by the Trump administration’s policy to transition firearms and firearm ammunition from the State Department’s purview to that of the Commerce Department’s Commerce Control List. As a result, the average risk score of a nation purchasing American weapons during the Trump administration is 41, compared to 39 under Obama and 37 during the Bush administration.

A second highlight from the report is that the risks of selling weapons depend not only on the purchasing nation, but also on the risk scores of its neighbors. Having risky neighbors makes it more likely that there is an active black market for stolen weapons in the region, that an active conflict will raise local demand for illegal weapons, and that American weapons will be misused, whether by the intended recipient or others. In this year’s index, we calculate the “neighborhood risk score” for each nation by averaging the risk scores of its contiguous neighbors. Using this measure, we find that China, Turkey, Saudi Arabia, Iran, and Sudan are the five countries in the riskiest neighborhoods. Turkey, Saudi Arabia, and Sudan collectively have received over $43 billion in US weapons since 2002.

To ensure the utility of arms sales and to limit the downsides, the data from the index suggest that the United States should consider two distinct policy changes. First, the United States should end weapons sales to the nations with the highest risk scores. Banning sales to serial violators of human rights, war-torn nations, and extremely fragile states will help prevent many of the most predictable harms from occurring. Second, Congress should take a more active role in debating and approving major arms sales. Public debate about the risks and benefits would force decision-makers to provide more thorough justification for arms sales and limit the number of high-risk, low-reward sales that currently make up a great deal of the American sales portfolio.