We have both a federal level of government and a state level of government to keep the balance of power and prevent one from overpowering the other.
Before the United States Constitution, there was the Articles of Confederation. The Articles of Confederation gave little power to the federal government and most of the power to the state governments. Under the Articles of Confederation, the federal government could not tax the states, draft soldiers, regulate trade, create and enforce laws properly, and other tasks.
Over time, this was inevitably harming the country. Since the federal government could not tax citizens, it was hard to advance the country or pay off war debts. Many people wanted change and for the federal government to have power, these people were called Federalists. On the contrary, the people who preferred the Articles of Confederation and the power to go to the state governments were called Anti-Federalists.
When the Constitutional Convention of 1787 occurred and the United States Constitution was created instead, a balance of power was needed. One of the main fears during this time was of the government obtaining too much power and abusing it on to the people, so the United States Constitution must have a balance of power between the two. So essentially, we have a federal level of government and a state level of government to create a balance between the two, preventing either of them from obtaining too much power.
