I think it's mostly left up to the States and their Secretaries of State on the voting process and rules and procedure. It's like that on the selection of electors as well, it's an extremely different procedure in each State. It would make more sense if there were finite deadlines and uniform rules for all 50 States, but that's not the way it is and it's not the way it's ever been. It's in the 10th amendment to the US Constitution- the powers not reserved to the United States by the Constitution nor prohibited by it to the States, "are reserved to the States respectively, or the people." Look it up, it's the law and has been since 1787. This is not some new development. It's called federalism and if you don't understand it, your ass flunks first year constitutional law. I see Canadian posters here who simply do not grasp this fundamental tenet of the American system.
I mentioned this post to my father and he brought up a very good point. He noted that States should be able to do whatever they want as per the 10th amendment for State elections, but that there should be standard rules and regulations for federal elections that should be promulgated on the federal level. He believes the 10th amendment needs to be challenged or amended to reflect this.