In Johnson v. Manhattan Railway Co., the U.S. Supreme Court ruled on a case involving an African American woman who was denied service by the Manhattan Railway Company due to her race. The plaintiff, Mrs. Marjorie Johnson, argued that this constituted racial discrimination and violated her rights under the Fourteenth Amendment of the Constitution which guarantees equal protection under law for all citizens regardless of their race or color. The defendants contended that they were private entities and therefore not subject to constitutional restrictions placed upon state actions. However, in its decision, the court held that while it is true that private corporations are generally not bound by constitutional limitations intended for government action only; when such corporations perform functions which are public in nature - like providing public transportation - they become agents of state action and thus must adhere to constitutional requirements. Therefore, denying service based on race was found unconstitutional as it violated Mrs.Johnson's Fourteenth Amendment rights even though done by a privately owned company performing a public function.

The dissenting opinion in the Johnson v. Manhattan Railway Co. case argued that the majority's decision to uphold a New York law requiring railroads to provide separate but equal accommodations for black and white passengers was incorrect. The dissenters believed that this law violated the Equal Protection Clause of the Fourteenth Amendment, which guarantees all citizens equal protection under the laws. They contended that segregation inherently implies inequality because it is based on racial prejudice and stereotypes, not any inherent differences between races. Therefore, they argued, any law enforcing segregation cannot be considered "equal" under the Constitution. Furthermore, they pointed out that such laws were often used as tools of oppression against minority groups rather than genuine attempts at ensuring equality.