A simple enough question it would seem. As Jim Grant so eloquently begins his oratory (describing how the Fed operates in contrast to how it was meant to operate per its founders) at Ron Paul's Fed Lecture Series from earlier in the year: "If one reads the Federal Reserve Act, you will be struck by how little the 21st Century model resembles the projected central bank - as in fact the founders advocated for a De-Centralized system." Note the specific wording at the end of the Act: "...to establish more effective supervision of banking in the United States; AND for other purposes." It is the 'other purposes' that provide the jumping off point for everything that has come since...
(h/t Sovereign Speculator [4])