Seymour v. Osborne was a United States Supreme Court case that dealt with the issue of whether a state could constitutionally prohibit the sale of lottery tickets. The case was brought by the plaintiff, Seymour, who was a lottery ticket seller in the state of Louisiana. The defendant, Osborne, was the state's attorney general. At issue was whether the state of Louisiana had the right to prohibit the sale of lottery tickets. The Supreme Court held that the state did have the right to prohibit the sale of lottery tickets, as it was within the state's police power to do so. The Court reasoned that the state had a legitimate interest in protecting its citizens from the potential harms associated with gambling, such as fraud and corruption. The Court also held that the state's prohibition of lottery tickets did not violate the Fourteenth Amendment's Equal Protection Clause, as the state had a rational basis for its prohibition. The Court reasoned that the state had a legitimate interest in protecting its citizens from the potential harms associated with gambling, and that the prohibition of lottery tickets was a reasonable means of achieving that goal. In conclusion, the Supreme Court held that the state of Louisiana had the right to prohibit the sale of lottery tickets, as it was within the state's police power to do so. The Court also held that the prohibition did not violate the Fourteenth Amendment's Equal Protection Clause, as the state had a rational basis for its prohibition.

In the case of Seymour v. Osborne, the Supreme Court ruled in favor of Osborne and against Seymour. The majority opinion held that a contract between two parties could not be enforced if it was made with an intent to defraud creditors or evade existing laws. Justice Field dissented from this ruling, arguing that contracts should generally be upheld regardless of their purpose as long as they are not illegal in themselves or contrary to public policy. He argued that courts should only interfere when there is clear evidence of fraud or illegality on the part of one party, which he did not believe was present here. Furthermore, he believed that allowing such interference would create uncertainty and instability in commercial transactions by discouraging people from entering into contracts for fear they may later be voided due to allegations of fraudulent intent.