Thank you for referencing that article Sopater. Please bear in mind that my critique about the article below is not being directed at you.
The referenced article is another good example of articles that address Constitution-related issues in a way that are at least inadvertently targeted to low information voters. More specifically. not only is there no clarification of what constitutonal clause(s) that the League of Women voters and Judge Richard Niess claimed that the law violated, but neither do we hear from the Wisconsin Supreme Court why they found the law constitutonal.
Note that states can prohibit otherwise eligible people from voting on the basis of anything not expressly protected by the Constitution. And the Constitution prohibits the states from not allowing people to vote on the bases of race, sex, tax owed and age as evidenced by the 15th, 19th, 24th and 26th Amendments respectively.
In other words, since no amendment or clause in the Constitution says that the states cannot prohibit people from voting if they can’t show a photo ID, then the states are free to prohibit people from voting on that basis.
But the states have to administer photo ID voting laws in a way that such laws don’t discriminate against poor people. This is because, although such laws are still constitutional imo, bleeding heart activist judges can probably get away with declaring such laws unconstitutional.