In Federalist #18, The Insufficiency of the Present Confederation to Preserve the Union, a continuation of the previous two essays, the scholarly James Madison turns to history and continues to outline the inadequacies of the Articles of Consideration. 
His core concern is to establish the fundamental weaknesses inherent in a system of government composed of multiple sovereigns under a relatively powerless central government.
Madison draws on examples from Greek history—essentially arguing that if Americans do not do away with the Articles of Confederation in favor of a system of government with a stronger national government, the country will ultimately repeat the tragic mistakes of the ancient Greeks.