The correct answer is: "Even tough equality of rights for all US citizens was included in the Constitution after the war, black citizens still had to fight for their rights due to the enactment of the Jim Crow laws in Southern states".
Although equality of rights for all US citizens had been already included in the US Constitution during the Reconstruction era, through the enactment of the 13th, 14th and 15th Amendments in 1865, 1868 and 1870 respectively, such equality did not happen in practice until one century later, after the preassure exercised by the Civil Rights Movement, that led to the enactment of the Civil Rights Act in 1964.
In the meantime, Southern states have enacted the so-called Jim Crow laws that aimed to prevent black people from accesing the rights that the Constitution had granted to them. For example, those laws imposed requirements to be able to access voting rights, for example, passing literacy tests or having a minimum income level. The result was that mostly black people was excluded from voting. Southern states also implemented segregation in public facilities under "the separate but equal lemma".
After the war black US citizens had to fight for their rights, even those were already included in the US Constitution. The federal goverment was responsible for enforcing those provisions and for providing means to guarantee the constitutional rights, although the federal goverment could not effectively achieve so until the enactment of the Civil Rights Act.
