HELP!!! Constitutional Law - Separation/collaboration of powers Forum

[Nono]

Hi everyone,

it's been weeks I am working on this question: in the United States, do separation of powers and collaboration of powers oppose themselves?

I don't know if I should talk about Federalism or not; I don't know if this question is about doctrines or practice or both; I don't know if it's about competencies or means of actions...Can someone help me?
I went through the concept of separation of powers history ( Montesquieu, Hegel,Locke, Rousseau, WIlson, etc...), I know how legislative, executive and judiciary powers function in the US but still, finding problematics pertaining to this very question is difficult for me.

Thank you in advance.