I am listening to the oral argument in Devillier v. Texas, and one attorney just said the declaratory judgment is an equitable remedy. It is not. Here is a note from the manuscript for the next edition of Ames, Chafee, and Re on Remedies:
Note on Equity and the Declaratory Judgment
Modern declaratory judgment acts have largely, but not entirely, superseded a variety of equitable remedies that were once quite important in solving procedural difficulties and providing effective protection for rights. Among these were quia timet (“because he fears”) relief, bills of peace, cancellation of documents, and decrees quieting title to property. In their original forms, these remedies all relied on the power of equity courts to issue in personam orders. Indeed, equity decrees are typically coercive: the court orders the defendant to do or not to do some act. This is one application of the maxim that equity acts in personam.
Even so, the ultimate goal of some equity proceedings is a declaration of the plaintiff’s rights vis-à-vis the defendant. Actions to rescind or reform a contract are examples. A request for an injunction may also have as its primary motive a declaration of rights between the parties. For example, in Huntworth v. Tanner, 87 Wash. 670 (1915), the plaintiff sued to restrain a threatened arrest and prosecution for violation of a penal statute, but the real relief at stake was a declaration that the plaintiff’s activities did not violate the law. Such injunctions are often called “anti-suit injunctions”: the plaintiff sues for an injunction to protect herself against a suit the defendant might bring in the future. Thus, a plaintiff would seek what was in effect a declaration, but using one of the traditional equitable forms of relief, because equity had no freestanding power to give declaratory judgments.
There are similarities between these equitable remedies and the modern declaratory judgment. For example, like an “anti-suit injunction,” the declaratory judgment can be seen as an “anti-suit” remedy. But there are even more differences. The declaratory judgment was created by statute, rather than being developed from equity. A plaintiff seeking a declaratory judgment does not have to meet basic equitable requirements, such as showing there is no adequate remedy at law. A declaratory judgment is not an in personam order, and it is not directly enforceable by contempt. Moreover, in some jurisdictions, a declaratory judgment action can be given by a jury. See generally Samuel L. Bray, The System of Equitable Remedies, 63 U.C.L.A. L. Rev. 530, 561–562 (2016); cf. Aetna Life Insurance Co. v. Haworth, 300 U.S. 227, 241 (1937) (upholding the federal Declaratory Judgment Act, and noting that “as it is not essential to the exercise of the judicial power that an injunction be sought, allegations that irreparable injury is threatened are not required”).
Perhaps it is best to see the declaratory judgment not as an equitable remedy, but as a legal prerogative writ, like mandamus or habeas. Because it lacks a traditional common law basis, the declaratory judgment had to be adopted by statute. Cf. Sir J.H. Baker, An Introduction to English Legal History 161 (5th ed. 2019).