A lawsuit seeking a declaratory judgment—also known as a “deck action” (dec. action)—is a lawsuit that asks the court to determine the rights, status, or other legal relations of the parties when a controversy has arisen, but before a wrong has been committed. A declaratory judgment seeks to prevent further litigation, liability, and harm. Declaratory relief is not available to settle disputes already pending before a court. A declaratory judgment is improper if the relief requested is raised for the first time in an amended petition (lawsuit) and merely addresses the same issues as were raised in the original petition.

A declaratory judgment is often sought when there is a disagreement over the meaning or application of an insurance policy or other contract, or a deed, will, trust, lease, statute, or municipal ordinance.

In New York, a declaratory judgment action, or 'dec action,' is a legal proceeding in which a party seeks a court's determination on the legal rights, duties, or status of the parties involved, typically before any actual harm or breach has occurred. This type of action is used to clarify legal relationships and to resolve uncertainty or disputes over the application of laws, contracts, insurance policies, wills, and other legal documents. The purpose of a declaratory judgment is to prevent further litigation or to provide parties with legal certainty. Under New York law, declaratory relief is not intended to resolve issues that are already the subject of ongoing litigation. Additionally, a declaratory judgment is not appropriate if it is sought through an amended petition that does not present new issues but rather addresses the same matters as the original petition. The New York Civil Practice Law and Rules (CPLR) govern the procedure for filing a declaratory judgment action in the state courts.