What document was the first form of national government created by the united states

Many people would say the Constitution, but the Articles of Confederation predate the Constitution.

"radical republicans  won over two-thirds of the seats in the house of representatives and the senate. they now had the power to override johnson's vetoes and pass the civil rights act and the bill to extend the freedmen's bureau, and they did so immediately. congress had now taken charge of the south'sreconstruction."