The document that served as a precursor to the Constitution in the United States was the Articles of Confederation. Ratified in 1781, this first constitution established a loose confederation of states with a weak central government. While it aimed to unify the newly independent states, it revealed significant limitations, such as the inability to levy taxes or regulate commerce, leading to economic instability. These shortcomings prompted the Constitutional Convention of 1787, ultimately resulting in the creation of the current U.S. Constitution.