A more thorough explanation:

Full faith and credit is a requirement in the United States Constitution that says state courts must respect the laws and judgments of courts from other states. This means that if a court in one state makes a decision on a legal issue, courts in other states must follow that decision if the same issue comes up in their state.

For example, if a court in California decides that a person is not guilty of a crime, and that person moves to New York and is charged with the same crime, the court in New York must respect the decision made in California and also find the person not guilty.

The full faith and credit clause is important because it helps prevent conflicts between states and ensures that legal decisions are consistent across the country. It also prevents people from going to different states to try to get a different outcome in their legal cases.

However, there are some situations where a court may not have to follow the decision of another court. For example, if the court that made the original decision did not have the authority to do so, or if the decision violates the Constitution.

One example of how the full faith and credit clause works is with marriage. If a couple gets married in one state, other states must recognize that marriage as valid. This means that if the couple moves to a different state, they are still considered married and have the same legal rights as they did in the state where they got married.