A more thorough explanation:

The Second Circuit Court of Appeals is a federal court that hears appeals from district courts in New York, Connecticut, and Vermont. It is one of the thirteen United States courts of appeals.

The Second Circuit Court of Appeals has made important rulings on the Commerce Clause, which is a provision in the United States Constitution that gives Congress the power to regulate commerce between states. In the case of American Libraries Association v. Pataki, the court ruled that a New York law that criminalized the dissemination of pornographic materials over the internet violated the dormant Commerce Clause.

The Commerce Clause applies to state laws that have an impact on interstate commerce. In the case of the New York law, the court found that it would have an effect on businesses and individuals in other states, and therefore was subject to scrutiny under the Commerce Clause.

The court also found that the internet is an instrument for commerce, and that state laws governing the internet must be part of a cohesive national scheme of regulation. The New York law was found to be inconsistent with other state laws and therefore unconstitutional.

For example, if a state passed a law that required all businesses to use a certain type of packaging for their products, and this packaging was only available from a company in that state, it would have an impact on businesses in other states that would have to purchase the packaging from that company. This law would be subject to scrutiny under the Commerce Clause.

In the case of the New York law, the court found that it would have a similar impact on businesses and individuals in other states who were using the internet to disseminate pornographic materials. The law would have required them to comply with New York's regulations, even if they were not located in New York.