The Constitutional Convention was called in 1787 to address issues with the Articles of Confederation, the first constitution of the United States. The Articles, which had been ratified in 1781, had several weaknesses, including a lack of power given to the national government to regulate commerce and enforce laws. Additionally, the national government could not levy taxes or regulate currency, which caused financial difficulties.
Another major issue with the Articles of Confederation was that it did not provide a means for amending the document. This meant that any changes to the Articles required the unanimous consent of all 13 states, which was highly unlikely to happen. This made it difficult for the national government to adapt to changing circumstances and address new issues as they arose.
The Constitutional Convention was called to address these issues and create a new constitution that would strengthen the national government and provide it with the necessary power to govern effectively. The convention was attended by representatives from 12 of the 13 states (Rhode Island did not attend) and was held in Philadelphia from May to September of 1787. The result of the convention was the United States Constitution, which was later ratified by the states and went into effect in 1789.