The issue of state separation of powers generally is not one that the federal courts have had much occasion to address. Recent issues have arisen, however, with respect to states’ use of private parties to enforce state anti-abortion regulations such as Texas’s Senate Bill 8 (S. B. 8), and as to state legislatures’ claims of near-plenary powers over federal elections under the so-called independent state legislature doctrine (ISLD). See Moore v. Harper, cert. granted, Jun. 30, 2022 (No. 21-1271). In addition, revived interest in the nondelegation doctrine, as illustrated in West Virginia v. EPA, raises questions as to the earlier impact of that doctrine. While nondelegation scholarship often focuses on the rare use of the doctrine to strike down statutes conferring powers on federal agencies, the federal courts’ use of separation of powers as to state delegations illustrates the effect of the doctrine in aid of other constitutional rights. This paper provides an account of the federal courts’ treatment of state separation of powers in the past, and then addresses the relevance of this account to current debates about S. B. 8 and ISLD.