There is no mandated form of ID in any state. How can you require people to have something to vote that is not required for any other purpose, at least if the government is not required to provide it?
Isn't that effectively the same argument though? In practice states provide ID's to everyone who can prove residency. Forcing states to grant ID's to everyone who asks for it is the same as forcing them to allow anyone to vote without ID's, just with an extra step.
You don't "force states to grant IDs to everyone who asks for it". You force states to issue IDs to all legal voters. States do not "provide IDs" to anyone - you are required to fill out paperwork, potentially travel and more.
In nations that do in fact have a national ID, everyone gets one, with little or no effort (certainly no need to travel), and if you wanted to mark the card "non-voting" that wouldn't be a big step.
Your right to vote is established by the US Constitution. A state can't burden that right. If a state wants to add an ID requirement, that's fine, but getting the ID must present no burden to any voter.
In reality, the conundrum here is entirely of conservatives' own making. On the one hand, they (non-exclusively) are adamantly against automatically issued national or even state IDs. On the other, they want to require ID for voting (ascribe whatever reason to this you want). You can't fulfill both these desires without violating the constitutional right to vote.
If you live without a vehicle in a rural corner of your state, compelling you to travel to somewhere else in order to get a state-sanctioned ID is, IMO, an undue burden.
If you are required to have documents and paperwork for a voter ID that you are not otherwise required to have, that is, IMO, an undue burden.
I have no problem with the state saying "you must have this document in order to vote" (it even makes a limited amount of sense, despite being a solution in search of a problem). I do have a problem with the state doing anything other than ensuring that every resident who should that document gets it with minimal effort (preferably zero).
