<span>Southern whites feared that freed blacks would seek revenge for past treatment</span>
The main failure of the Articles of Confederation was that it gave too much power to the states, basically the states were all divided into their own governments. The national government have too little power and couldn't properly control the states. The US Constitution was created to balance out the powers between state and national government.
The mother country did this to protect its trade from suffering loss. Achenwall's Observations on North America Gottfried Achenwall.