At the last battle of the American Revolution the British were stranded because of the french warships on the sea and the Continental Army on the land. The British lost because mistakes in their tactics.
Confusion among the states
States wrote state laws and rights because there was no real national government. Most states wrote their own constitutions that set taxes and state legislature.
The articles provided a weak link between the colonies. It had many flaws such as the inabilty to tax the colonies.
The Constitutional Convention
All the states made their own currency which caused confusion with trade and value of money. Nine out of the 13 states had to argee to pass a law and all the states had to agree to change the Articles of Confenderation.
Then we had a depression where farmers couldn't sell their crops and they lost their homes because they couldn't pay taxes. They were outraged and burned homes of officals. This proves that the articles of confenderation were weak.
All the states expect Rodhe Island sent representives to the convention to disscuss a national document. Most of the states sign the document ,bu some don't because they don't want too much national power.