the president is dependent upon the legislature to approve his foreign policy preferences and to provide the necessary funding, and thus the ability to make law and the power of the purse gives Congress significant leverage to set the tone of American foreign policy—if they choose to use it.
Press release: A Balance of Powers: How Congress and the President Shape Foreign Policy 
Image credit: ANUJAK JAIMOOK 
- “A Balance of Powers: How Congress and the President Shape Foreign Policy”: https://www.rstreet.org/2019/10/30/a-balance-of-powers-how-congress-and-the-president-shape-foreign-policy-2/
- “ANUJAK JAIMOOK”: https://www.shutterstock.com/g/anujak+jaimook