Answer: violated the Fourteenth Amendment's Equal Protection clause
Explanation:
Plessy claimed the law violated the Fourteenth Amendment's Equal Protection clause, which requires that a state must not “deny to any person within its jurisdiction the equal protection of the laws.” The Supreme Court disagreed with Plessy's argument and instead upheld the Louisiana law.
That would go against the 10th amendment say states make their own laws
Federal as the picture says in bold it is federal.
I would say interest groups
