Before the Constitution was drafted, the nearly 4 million inhabitants of the 13 newly independent states were governed under the Articles of Confederation and Perpetual Union, created by the Second Continental Congress, first proposed in 1776, adopted by the Second Continental Congress in 1778 and only finally unanimously ratified by the Original Thirteen States by 1781. It soon became evident to nearly all that the chronically underfunded Confederation government, as originally organized, was inadequate for managing the various conflicts that arose among the states.:4–5:14–16 As the Articles of Confederation could only be amended by unanimous vote of the states, any state had effective veto power over any proposed change. In addition, the Articles gave the weak federal government no taxing power: it was wholly dependent on the states for its money, and had no power to force delinquent states to pay.
Once the immediate task of winning the American Revolutionary War of 1775 to 1783 had passed, the states began to look to their own interests, and disputes arose. These included a dispute between Maryland and Virginia over the Potomac River and opposition to Rhode Island's imposing taxes on all traffic passing through it on the post road. James Madison suggested that state governments should appoint commissioners "to take into consideration the trade of the United States; to examine the relative situation and trade of said states; to consider how far a uniform system in their commercial regulations may be necessary to their common interests and permanent harmony".:92
Another impetus for the convention was Shays' Rebellion of 1786-1787. A political conflict between Boston merchants and rural farmers over issues including tax debts had broken out into an open rebellion. This rebellion was led by a former Revolutionary War captain, Daniel Shays, a small farmer with tax debts, who had never received payment for his service in the Continental Army. The rebellion took months for Massachusetts to put down completely, and some desired a federal army that would be able to put down such insurrections.
These and other issues greatly worried many of the Founders that the Union as it existed up to that point was in danger of breaking apart, and being subject to the persuasion of foreign powers.
In September 1786, at the Annapolis Convention, delegates from five states called for a Constitutional Convention in order to discuss possible improvements to the Articles of Confederation. The subsequent Constitutional Convention took place in Philadelphia, convening in the Old Pennsylvania State House (then becoming known as Independence Hall) on May 14, 1787. Rhode Island, fearing that the Convention would work to its disadvantage, boycotted the Convention and, when the Constitution was put to the states during the next year of controversial debates, initially refused to ratify it, waiting until May 1790 to become the thirteenth, a year after the new federal government commenced.