How did the north get the south to obey federal laws and respect the freedmen after the civil war during reconstruction?

During Reconstruction, the North employed various measures to ensure compliance with Federal Laws and protect the rights of freedmen in the South. This included the establishment of military districts in the South, the enforcement of the Reconstruction Acts, and the ratification of the 13th, 14th, and 15th Amendments to the Constitution. Additionally, the Freedmen's Bureau was created to provide assistance and support to newly freed slaves.