Justice Harlan had a level of understanding of both the 14th and 13th amendment that revived modern day Scholars. He used them well in his dissent during the Plessy v. Ferguson case. Harlan knew not only the wording of the amendments but the spirit of them. He looked past present circumstances and analyzed the ultimate impact.
Justice Harlan interpreted the 13th amendment in a way that expands its meaning. He saw the 13th amendment as way to abolish slavery and any marking and situations of slavery. He saw the law for its spirit.
More important to the case is his interpretation of the 14th amendment which explains that 14th amendment prevents making distinction by color illegal. Louisiana violates this principle with their separated cars. Louisiana was called out by Harlan because they used the technical wording of the amendment to slide past the true meaning of the law.
Justice Harlan was originating the concept that the constitution was color blind. After instating that Black American were citizens and therefore had all legal rights. Expanded this idea by stating that they were therefore entitled to equal treatment legally and in the marketplace.
Justice Harlan’s dissent might be one of the most important documents pertaining to civil rights and it even informed Brown v. Board later down the line. It introduce America to some of its most important concepts and continue to inform our analysis of the the 13th and 14th amendments
https://www.thinkwy.org/post/justice-harlans-imperishable-dissent-in-plessy-v-ferguson#:~:text=Justice%20John%20Marshall%20Harlan%20was,Bd.