Typically, a legal judgment cannot be invalidated solely because it arises from an activity that would be deemed illegal where enforcement is sought. Once a court with proper authority adjudicates a matter, its judgment is usually conclusive, despite any potential illegality involved in the underlying transaction. This is supported by the principle of finality of judgments.
For example: A Nevada court’s judgment rewarding gambling debts may need to be enforced by courts in another state where gambling is illegal, except where enforcement contravenes that state’s public policy.