Final answer:
The court case that strengthened the Jim Crow laws was Plessy v. Ferguson.
Step-by-step explanation:
The court case that strengthened the Jim Crow laws was Plessy v. Ferguson. In this case, the Supreme Court ruled in 1896 that racial segregation was constitutional as long as the separate facilities were deemed to be equal. This decision set the precedent for the legally enforced racial segregation that persisted in the United States for many decades.
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