As they say, I am not a Supreme Court Justice, but states in fact do not elect presidents in a presidential election. They elect state-based electors, which cast their votes for president. There are no federal administrators of elections: these powers are indeed reserved to the states.
The 14th Amendment is not about the election process, it's about who can hold office. For example, it's pretty clear that legislators violating their oaths on Jan 6th forfeited their right to serve in Congress or any other federal office. They need not be indicted or tried for insurrection, their participation is as straightforward a disqualification as the age and nativity qualifications. A number of them should be booted right now.
That said, nothing about the 14th Amendment constrains who can be on the ballot; it merely disqualifies any insurrectionist from being seated, absurd as that sounds. You can vote for anyone - whether they are qualified or not. The timeline is irrelevant, so if there are FURTHER insurrection attempts between now and Jan 2025, those restrictions still apply to other insurrectionists running for federal offices. That's right, I'm accounting for yet another insurrection in the hot summer of '24.
So the question remains: which authority enforces these restrictions? It probably should be whomever is administering the oath. Should Trump actually select a Vice President who was not an insurrectionist, then by the order of succession, that person would become president. If not, so on through the presidential line of succession.
