The Fourteenth Amendment

XIV
Section 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.

Section 2. Representatives shall be apportioned among the several States according to their respective numbers, counting the whole number of persons in each State, excluding Indians not taxed. But when the right to vote at any election for the choice of electors for President and Vice President of the United States, Representatives in Congress, the Executive and Judicial officers of a State, or the members of the Legislature thereof, is denied to any of the male inhabitants of such State, being twenty-one years of age, and citizens of the United States, or in any way abridged, except for participation in rebellion, or other crime, the basis of representation therein shall be reduced in the proportion which the number of such male citizens shall bear to the whole number of male citizens twenty-one years of age in such State.

Section 3. No person shall be a Senator or Representative in Congress, or elector of President and Vice President, or hold any office, civil or military, under the United States, or under any State, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any State legislature, or as an executive or judicial officer of any State, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof. But Congress may, by a vote of two-thirds of each House, remove such disability.

Section 4. The validity of the public debt of the United States, authorized by law, including debts incurred for payment of pensions and bounties for services in suppressing insurrection or rebellion, shall not be questioned. But neither the United States nor any State shall assume or pay any debt or obligation incurred in aid of insurrection or rebellion against the United States, or any claim for the loss or emancipation of any slave; but all such debts, obligations and claims shall be held illegal and void.

Section 5. The Congress shall have power to enforce, by appropriate legislation, the provisions of this article.

This is the longest of the Reconstruction amendments, and it is referenced fairly frequently for court cases. 

Looking at the different sections, Section 1 comes right out and overturns the Dred Scott decision, saying that those of African descent could never be citizens. If they were born here, there were citizens, black or white. (I would say no matter what color, but that required some time.)

This section should nonetheless have covered all of the freed slaves. Based on the ending of slavery in Canada in 1833, Mexico in 1829 (despite reinstatement by Texas), and the end of purchasing new slaves from Africa, and the United States abolishing the African slave trade around 1807 (it took about a year to take effect), that by the 1868 ratification, it should have covered all African-Americans. They were now entitled to due process and equal protection. The Equal Protection clause is one element that is referred to often.

There was an understanding that some states were still going to have a hard time with this, with gives us the next two sections. If you do not count these citizens, it is coming out of your representation. Your representatives also need to not have been rebels, and we can pardon them for that, but this is going to remain a union, with Black men as citizens.

There are still questions about counting Native Americans - ostensibly a question of sovereignty, though that seems arguable based on the enforced relocations. (Just another reminder that we still have race problems because we have clung to them so tightly.)

Inclusion that there will be no payment for the loss of slaves seems like a practical issue - preventing the government from drowning in claims, but can also serve as a statement that no one should have had slaves in the first place. It could also be helpful when new cases arise of people trying to get around slavery, which happened a lot.

Finally, that final clause reminding that this can and will be enforced. Sadly, in a few years the North would decide that it was more important to placate the hurt feelings of the South than protect the new citizens, but we will keep coming back to it as many times as it takes: Brown versus the Board of Education, Obergefell versus Hodges, and many more.