Many aspects of the Constitution are a reaction against the problems that plagued the American colonies and the early American nation. Most of the freedoms provided by the Bill of Rights were instituted in order to protect against the abuses levied by Parliament against the colonists prior to the American Revolution. The Anti-Federalists were worried that a new central government would become aloof to the needs of the people and trample basic liberties, such as freedom of speech and the right to jury trials. In order to ensure that this did not happen, the Framers explicitly safeguarded what they regarded as basic freedoms in order to protect people from the overreaches of the national government.
The other issue that the Framers tried to fix was the general ineffectiveness of the government under the Articles of Confederation. The Continental Congress could not make the states pay taxes; therefore, the government could not pay its creditors at home or abroad.
The Constitution created by the Framers consisted of three branches of government. Each branch had its own set of duties. The Framers also created a system of checks and balances, so that no one branch became more powerful than the others. In order to ensure that the federal government would not become too powerful, the Bill of Rights also ensured that states would retain power with the Tenth Amendment.