Last week, the State Department announced that it would revoke the designation of Yemen’s Houthi rebels as a terrorist organization. This would reverse one of the big decisions of the closing days of the Trump administration, which not only designated the Houthis a Foreign Terrorist Organization (FTO) but also designated Cuba as a State Sponsor of Terrorism.

Presumably, the outgoing president was trying to tie the Biden administration’s hands in its future foreign policy. To understand how, and the consequences of last week’s decision, it is important to understand what “designation” is in the first place.

U.S. designation tools are supposed to target international criminals, terrorists and enemies of the U.S.

When the U.S. designates individuals, organizations or countries, it adds them to a list, telling the world that the designated target has been identified as a security risk and thereby isolating them. Being placed on these lists can trigger sanctions and facilitate prosecution. A designated individual can be arrested, banned from travel or have their assets frozen. If a bank helps designated entities move money, the U.S. may levy big fines and ban that bank from clearing transactions in U.S. dollars, thus jeopardizing its international business.

The most important of these lists are the FTO list and the State Sponsors of Terrorism list of the State Department, and the Specially Designated Nationals and Blocked Persons (SDN) list of the Treasury Department.

The United States uses designation to achieve key security and foreign policy goals, such as preventing a government from acquiring a nuclear weapon or weakening armed groups that use terrorist tactics. Designation tools are thus commonly used against individuals, organizations or countries involved in terrorism, proliferation, money laundering and other international crimes.

In deciding what entities to list, the United States has traditionally considered how much damage the potential target is doing, but balances that against U.S. foreign policy goals. That’s why some entities that might seem obviously right for the FTO list, such as the Taliban in Afghanistan, are not in fact on it. Designating the Taliban would complicate any future negotiations, which the United States saw as necessary to achieve its foreign policy goals.

That changed under the Trump administration

That changed under the Trump administration, which often used designations to appeal to Republican voters rather than to achieve strategic foreign policy goals. Domestic politics have always played a background role in the designation process, but in the past four years, they have come to the fore.

For instance, the Trump administration designated two International Criminal Court officials by putting them on the SDN list, which is supposed to target international criminals and terrorists. Their purported offense was “having directly engaged in an effort to investigate U.S. personnel,” because the ICC decided to investigate alleged war crimes committed in Afghanistan. The administration’s unprecedented decision led the United Nations and U.S. allies to condemn it, and civil society groups to successfully challenge the designation in U.S. courts.

The administration’s last-minute designation of Cuba as a sponsor of terrorism was also unprecedented in the lack of obvious foreign policy justification, and may have been done because the administration wanted to please constituents in states like Florida.

Furthermore, when the Trump administration designated a white supremacist organization, it chose an obscure group, the Russian Imperial Movement, and designated it in a less far-reaching way than the FTO list would have provided for.

Other decisions were equally unprecedented

The Trump administration was hardly the first U.S. administration to sanction entities in Iran, but there too it set precedents. For instance, it added the Islamic Revolutionary Guard Corps (IRGC) to the FTO list, marking the first time that the United States had so designated part of a foreign state’s military apparatus. Claiming that a nation’s military are terrorists (rather than merely calling the nation a “sponsor” of terrorism) may raise tricky legal questions in the future, and can put U.S. soldiers at risk. Meanwhile, the designation had little practical benefit, since any entity that might have been put off by the listing had already stopped doing business with the IRGC.

Moreover, experts had warned that designating the Houthis as an FTO would impede aid delivery to the world’s worst humanitarian crisis by criminalizing aid workers and compromising cease fire negotiations. As designation makes engaging with members of an FTO a crime, it exposes humanitarian groups to legal liability because they need authorizations from the Houthis to carry out aid programs.

The decision to designate was therefore particularly controversial, considering the way people are dying in Yemen. While Houthi-controlled areas have been subjected to over 22,000 air raids, the United Nations reported that the majority of the 230,000 casualties in the conflict have died through indirect causes such as lack of food and health services. It is because of these humanitarian concerns that the Biden administration decided to roll back the designation.

However, the Trump administration also made some designation decisions on the basis of more traditional security assessments and foreign policy goals. For example, by removing the defunct East Turkestan Islamic Movement from the foreign terrorist list, the administration made it harder for China to justify its treatment of Uighurs in the Xinjiang region.

The Biden administration’s response

Even apart from the decision on the Houthis, the Biden team has already made cleaning up designations a priority. The new administration has paused many of the previous administration’s 11th-hour designations for further review, and announced a broad review of sanctions operations. But it will be difficult to restore the norms that limit the use of designations, and to prevent sweeping or questionable use of designations in the future.

Manuel Reinert is a PhD candidate at American University, consultant with the World Bank, and adjunct lecturer at Georgetown University.

Samuel M. Hickey is a research analyst at the Center for Arms Control and Non-Proliferation.