Bilateral development assistance: This is the type of aid that most resembles common perception. Given to governments or organizations such as the Peace Corps and the Inter-American Development foundation. These are to assist in long-term projects to promote democracy, economic growth, stability and development.
Aid to support U.S. Security Objectives: The U.S. reserves a large amount of its foreign aid to be invested specifically in projects that correlate with American interests and objectives. Most recently, this has been in promoting stability in the Middle East. Before, during the cold war, it was supporting emerging Eastern European countries. A savvy investor, the United States has wisely been operating on the principle that prevention is better than cure.
Humanitarian Assistance: Though this can be confused with bilateral development assistance, the main difference is that humanitarian assistance is often in response to urgent short term needs, such as food crises, natural disasters or other major humanitarian emergencies. Recent examples would be the tsunami in Southeast Asia or the Syrian conflict.
Military Assistance: As the name suggests, this is when the U.S. allows ally countries access to American equipment and training. Though it declined somewhat before the War on Terror began, military training is the most controversial of the types of aid, not only for the moral implications but also for the inherent dangerous in weaponizing a country.
Multilateral Assistance: In multilateral assistance, the U.S. works with other countries to pool funds into international organizations such as UNICEF, the UNDP or the World Bank. Though this sector constitutes a minority of the US’s foreign aid, the nation’s contributions make up a significant percentage of the donor funds received by the organization.
– Farahnaz Mohammed
Source: Congressional Research Service