Which International Relations theory provides the greatest clarity regarding the interactions of international actors and why?

Which International Relations theory provides the greatest clarity regarding the interactions of international actors and why? The sources I have to use for this question are: file:///C:/Users/18049/Downloads/Why%20Liberalism%20Explains%20the%20World.pdf  file:///C:/Users/18049/Downloads/The%20World%20Wants%20You%20to%20Think%20Like%20a%20Realist%20%E2%80%93%20Foreign%20Policy.pdf How does the “friction” between the three branches impact foreign policy decisions?    The sources I have to use for this question are: file:///C:/Users/18049/Downloads/Carlisle,%20How%209-11%20Expanded%20the%20Power%20of%20the%20Gov’t.pdf *I also need 4 paragraphs for both questions. And each paragraph has to have at least 10 sentences*