Arizona is perfectly within its rights to determine who may/not vote and by what mechanism that determination is made.
The Federal government is interfering with Arizona’s right.
Me thinks you ought to read the Constitution:
Article I, Section IV:
1: The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof; but the Congress may at any time by Law make or alter such Regulations, except as to the Places of chusing Senators.
Congress mandated that registration for federal elections be done on a federally-authorized form. That form DOES NOT currently specify a requirement to prove citizenship ...
States have always controlled who voted.
Prior to the adoption of Amend. XV some states denied suffrage on account of race, color, or previous condition of servitude.
Prior to the adoption of Amend. XIX some states denied suffrage to women.
Amendments were required to extend suffrage.
According to the DOJ (http://www.justice.gov/crt/about/vot/nvra/nvra_faq.php), Section 6 of the NVRA provides that a State can develop its own form, if it meets all of the same criteria the NVRA requires for the EAC’s national mail voter registration application.
There is no mention of limiting a State form to only the criteria on the national form.
Additionally, "The voter registration portion of the application may not require any information that duplicates information required on the driver’s license portion of the application and may require only the minimum amount of information necessary to prevent duplicate voter registrations and permit State officials both to determine the eligibility of the applicant to vote and to administer the voting process."
"The voter registration application must state each voter eligibility requirement (including citizenship), contain an attestation that the applicant meets each requirement, state the penalties provided by law for submission of a false voter registration application and require the signature of the applicant under penalty of perjury."
How does an applicant's attestation permit State officials to determine the eligibility of the applicant? The State can make no such determination, only passively accept the application. How can the State determine the veracity of the attestation? This ruling neutralizes the State's ability to determine the eligibility of the applicant.
All the above aside, Congress has no authority. This is the flaw in the ruling.