"The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof; but the Congress may at any time by Law make or alter such Regulations, except as to the Places of chusing Senators.
Seems simple enough, but the case boils down to what "the Legislature thereof" refers to. The majority decision describes the conflict here:
The Arizona Legislature’s complaint alleged that “[t]he word ‘Legislature’ in the Elections Clause means [specifically and only] the representative body which makes the laws of the people,” App. 21, ¶37; so read, the Legislature urges, the Clause precludes resort to an independent commission, created by initiative, to accomplish redistricting. The AIRC responded that, for Elections Clause purposes, “the Legislature” is not confined to the elected representatives; rather, the term encompasses all legislative authority conferred by the State Constitution, includ Cite as: 576 U. S. ____ (2015) 3 Opinion of the Court ing initiatives adopted by the people themselves.
Some background info on the clause itself:
- The Heritage Foundation: Election Regulations.
- The Founders' Constitution: Article 1, Section 4, Clause 1.