A more thorough explanation:

Ashwander rules refer to a set of principles that guide the U.S. Supreme Court in deciding constitutional questions. These rules were outlined in Justice Brandeis's concurring opinion in Ashwander v. Tennessee Valley Authority in 1936.

The Ashwander rules include:

• The court should not decide a constitutional question in a friendly suit.
• The court should not anticipate a question of constitutional law.
• The court should not create a rule of constitutional law that is broader than that called for by the facts of the case.
• The court should not decide a constitutional issue if the case can be decided on another ground.
• The court should not rule on the constitutionality of a statute unless the plaintiff is harmed by the statute or if the plaintiff has accepted the benefits of the statute.
• The court should not rule on the constitutionality of an act of Congress without first analyzing whether the act can be fairly construed in a way that would avoid the constitutional question.

For example, if a person challenges a law that they have not been affected by, the court may not rule on the constitutionality of the law. Similarly, if a case can be decided on a non-constitutional issue, the court may avoid ruling on the constitutional question.

The Ashwander rules help ensure that the Supreme Court only decides constitutional questions when necessary and avoids creating broad rules that may have unintended consequences.