Once again, the U.S. Supreme Court has acknowledged that when state legislatures undertake functions under Article V of the Constitution, they do so as independent assemblies. Signature by the governor and other lawmaking formalities are not necessary. The latest acknowledgement came in the court’s June 27, 2023 decision in Moore v. Harper (pdf).
State legislatures’ roles as bodies initiating (via convention) and ratifying constitutional amendments are only two of several “federal functions” (pdf) the Constitution assigns to persons and entities outside the federal government. In Moore v. Harper, the court had to determine whether the Constitution’s Election Clause (Article I, Section 4, Clause 1) granted authority to apportion congressional districts to the state legislature acting alone or as part of the state’s larger legislative apparatus. The court decided the latter. In doing so, however, it distinguished the case before it (which involved lawmaking) from other functions the Constitution assigns to state legislatures:
Leser v. Garnett, 258 U. S. 130 (1922). . . addressed an argument that the Nineteenth Amendment—providing women the right to vote—was invalid because state constitutional provisions “render[ed] inoperative the alleged ratifications by their legislatures.” . . . We rejected that position, holding that when state legislatures ratify amendments to the Constitution, they carry out “a federal function derived from the Federal Constitution,” which “transcends any limitations sought to be imposed by the people of a State [in the state constitution or laws])” . . . .
But the legislature in Leser performed a ratifying function rather than engaging in traditional lawmaking. The provisions at issue in today’s case—like the provisions examined in Hildebrant and Smiley—concern a state legislature’s exercise of lawmaking power. . . . Lawmaking under the Elections Clause, Hawke [v. Smith] explained, “is entirely different from the requirement of the Constitution as to the expression of assent or dissent to a proposed amendment to the Constitution.” . . .
Legislatures act as “Consent[ing]” bodies when the Nation purchases land, Art. I, §8, cl. 17; as “Ratif[ying]” bodies when they agree to proposed Constitutional amendments, Art. V; and—prior to the passage of the Seventeenth Amendment—as “electoral” bodies when they choose United States Senators . . . .
By fulfilling their constitutional duty to craft the rules governing federal elections, state legislatures do not consent, ratify, or elect—they make laws. [The court then concluded that legislative actions under the Election Clause, unlike under Article V, were subject to state constitutional rules applying to legislation.]
There is an extensive body of Article V Law, discussed in this treatise.