The United States Constitution provides that rules for the election of congressional representatives for each state shall be set by the “Legislature thereof.” Last Term, in Arizona State Legislature v. Arizona Independent Redistricting Commission, a Supreme Court majority joined by Justice Anthony Kennedy permitted Arizona to bypass its formal legislature and adopt congressional district lines drawn by an independent commission pursuant to an authorization from the people of the state. Commentary on Justice Kennedy’s vote suggested that practical policy considerations moved him to approve this reassignment of legislative power. But placing Arizona State Legislature in its proper context suggests that a deep principle was at work: while the federal Constitution carefully assigns federal legislative, judicial, and executive powers to specific institutions, it leaves the states free to allocate such powers differently. Justice Kennedy’s opinion for the Court in ASARCO, Inc. v. Kadish allowed a state to have its judicial branch make decisions more typical of an executive agency, and to have private proponents defend those decisions to the Supreme Court. The outlier in this trilogy was Hollingsworth v. Perry. There, over Justice Kennedy’s vigorous dissent, the Court prevented a state from granting executive power to private proponents, and declined to hear their substantive arguments. Analyzing the cases together reveals striking parallels and provides a new perspective on Hollingsworth’s anomalous holding.