What does the term “co-operative federalism” mean? Explain with reference to the evolution of federalism in the United States.

Given Instructions: Your essay should be around 1900 words or more exclusive of footnotes (endnotes) and bibliography. It must be typed, properly footnoted, and include a bibliography of the books, articles, and other source material (including those from the internet) used for the assignment. You will be given a zero mark if your assignment is not properly footnoted or does not include a bibliography.

I need at least 10 sources and the structure of the essay must be Introduction-Body1-Body2-Body3-Body4-Body5-Conclusion.
Also, because I am Japanese, the quality of the essay can be imperfect.
Thank you.