The Elections Clause does not free state legislatures from state constitutional constraints and state judicial review.
Purcell v. Gonzalez, 549 U.S. 1 (2006)
Cautions federal courts about election-rule changes close to an election. Both sides can invoke “status quo” differently here: the legal status quo is the 2022 map under the Missouri Supreme Court's judgment; the practical election status quo is the HB 1 districts used in the August primary.
Shapiro v. McManus, 577 U.S. 39 (2015)
Bears on when a three-judge district court must be convened.
Constitutional challenges to congressional apportionment ordinarily require a three-judge district court. A single district judge has limited TRO authority but cannot perform every function reserved to the three-judge court. This may become an important appellate issue.
Before certification and review resolved sufficiency, merely submitting the referendum did not automatically settle HB 1's status. Once SC101805 determined the petition legal, sufficient and timely, the legal consequence was that HB 1 never took effect.