<span>United Nations (UN)
North Atlantic Treaty Organization (NATO)
European Union
Explanations: The United States is a member state of United Nations (UN), a world body of 193 sovereign states, and agrees with its principles. as this is a major world organization and the United States has a permanent ambassador to UN, it greatly assists a president in implementing his foreign policy.
Another one foreign organization is North Atlantic Treaty Organization (NATO). As NATO is an important organization mainly for national security whose members cooperate in exchanging security and diplomatic related issues, it vitally assists a president in implementing his foreign policy.
The third foreign organization is European Union (EU). The United States is a close partner of EU and has a great relationship with it. NATO has head quarters in Brussels, Belgium, a member state of EU. EU is also closely shares security related issues with the United States. Thus, it assists a president in implementing his foreign policy.</span>
