Federalist No. 48
Federalist No. 48, authored by James Madison under the pen name Publius, is the forty eighth of 85 essays. Titled "These Departments Should Not Be So Far Separated as to Have No Constitutional Control Over Each Other", Madison points out that while the departments can be connected, they should in general remain "separate and distinct" in our "representative republic".
It was published on February 1, 1788.
Madison's greatest fear for the newly formed Constitution was legislative over-reach, citing Virginia and Pennsylvania as two examples. He cites a report by a "Council of Censors" which investigated violations of the Pennsylvania Constitution.