I believe it would be: To outline key ideas in support of the constitution. This is most likely the answer because when the Federalist papers were made many Americans realized that the articles of confederation weren't very effective, so delegates met in Philadelphia in 1787 to create the constitution, which was met with heavy criticism. The Federalist Papers is one of the main reasons the constitution ended up succeeding.
Hope this helps! Feel free to message me if you have any questions or need more help! :)