Gordon_4 said:
Jesus that's....depressing.
More specifically, it's handled at the county level because that's the level that's closest to the ground but still has the resources to actually do it.
Imagine going the other direction, and handing it federally. Which means the federal government now has to keep track of every office in every city and county nationwide, and exactly which subset of people are allowed to vote for each one. That gets complicated. Very complicated. Hell, the smallish town where I went to college some of the citizens were voting in different county elections than others because the county line split through the middle of town.
But yeah, the electoral rolls are in pretty bad shape, simply because it's not on people's minds to keep their address up to date with the county office and the electoral rolls aren't linked to any other database about folks.
There's a federal law that says that you can only remove a voter from the rolls in very narrow circumstances, most notably if they've moved or died. Since the voter rolls are not connected to anything else, it also outlines a procedure to function as minimum evidence someone has moved or died since moving or death is often not reported to the election rolls:
[ol]
[li]The person must miss two consecutive federal elections.[/li]
[li]The person must be sent a mailer, requesting they either update their info or vote to remain on the rolls.[/li]
[li]The person must not respond to that mailer.[/li]
[li]The person must not vote in the following federal election.[/li]
[li]No one can be removed too close to an election day (it's either 30 or 90 days, I don't recall offhand).[/li]
[/ol]
At that point, it's considered sufficient evidence that that person is no longer present at that address, and thus can be safely removed from the rolls.
There are two elements to the whole "voter purges" thing - one is that a lot of valid voters get purged because they simply don't vote, moved, and never updated their address. Which means that voter appears to be no longer at that location, which means they can be dropped. The other is that certain states have a marked increase over the average in how many people they've removed from the roll the last couple of years.
This is tied explicitly to the Voting Rights Act, which established that based on a formula supplied by Congress that certain states would be subjected to additional federal oversight in how they conduct their elections. A court case functionally overturned that on the argument that the formula to determine who should be subjected to additional oversight had not been updated since the 70s and that the sociopolitical landscape is different enough now than then as to make it meaningless. The court agreed, and struck down the formula that's in place and without an indication of who is supposed to get additional federal oversight, no one is subjected to it. Which means even the deep south is only subject to the same federal election rules as New York, and not extra scrutiny. As soon as the extra scrutiny was removed, they picked up markedly in how many names were pulled from the rolls each year.