Two neighbours in the same state can vote on different equipment, on different ballot layouts, under different early voting hours. Election administration in the United States is local by design rather than by accident.
The Constitution assigns the task to states
Federal law sets certain baselines, including the date of federal elections and protections in areas such as accessibility and voter registration.
The mechanics of running an election, meaning how ballots are printed, where polling places sit and how results are counted, are left to the states.
Most states then delegate that work downward to counties or, in a few places, to townships and municipalities.
Thousands of jurisdictions each own their own process
The practical result is that the country runs several thousand simultaneous elections rather than one. Each jurisdiction procures its own equipment, trains its own workers and manages its own rolls.
Ballots differ within a state because they must, since local races, judicial retentions and municipal measures vary street by street.
Even within one county there may be dozens of distinct ballot styles, each printed for a specific combination of districts.
Local funding produces uneven capacity
Election offices are typically funded from county budgets, competing with roads, policing and public health for the same money.
A populous county can afford high-speed scanners, permanent staff and a dedicated warehouse. A rural one may run an election with a handful of employees and seasonal volunteers.
That gap explains much of the visible variation in wait times, equipment age and how quickly results are reported.
Counting rules explain the reporting differences
States differ on when mail ballots may begin to be processed, and processing is slow work involving signature checks and envelope opening.
Where processing may start before election day, mail results appear early. Where it may not, those ballots are counted afterwards, and totals shift for days as they are added.
The same is true of overseas and military ballots, which arrive under separate deadlines set by state law.
The structure has trade-offs in both directions
Decentralisation means no single system can be compromised at scale, and it keeps administration close to the people it serves.
It also means standards, funding and reporting speed vary widely, which is the source of most disputes about how elections are run. Both consequences follow from the same design choice.