Being a masochist at heart, I will try to introduce some facts in to the Arizona decision discussion. I doubt it will do any good here.
Let's look at this logically and not emotionally. Can Arizona implement a law that requires citizens to prove their citizenship?
First we need to start with the basis of our system of laws, the United States Constitution. Specifically Article 1 section 4
This means that the States are free to make the laws governing how they run federal elections but the Congress has the authority to change these laws. However, the Congress must change these laws through legislation.
In 1965, the Congress did so.
Voter Rights Act 1965 PL 89-110 42 U.S.C. 173 was that law and the federal regulation is represented by 28 CFR Part 51. One of the provisions of the VRA was that any changes to a state's federal election law must be pre-screened by the United States District Court for the District of Columbia or, in the case of an election regulation be pre-screened by the United States Department of Justice. Arizona is one of those states subject to this pre-screening requirement.
This means that before Arizona can either change or implement a law affecting how Arizona runs federal elections, this change or implementation must be pre-screened by the US District Court for DC. Since this was not done, the proposed Arizona law is in conflict with the VRA and therefore is in violation of the Election Clause of the Constitution.
The National Voter Registration Act of 1996 PL 103-31 and 107 Stat. 77 governs how people can register, in their states, to vote in Federal Elections.
Under this law, there are three methods, and only three methods in which someone is allowed to register to vote in Federal Elections. The state does not have the authority to change this.
1. The first method of voter registration is described in Section
3, § 1973gg-3. This section provides that any application
for a driver’s license submitted to a state motor vehicle
authority “shall serve as an application for voter registration
with respect to elections for Federal office unless the applicant
fails to sign the voter registration application.”
2. The second method of voter registration, set forth in Section
4, § 1973gg-4, requires states to register federal voters by
mail using the Federal Form.
The form asks for either a SSAN or a Driver's license number. Barring that, the state will assign an identification number and the state sets the procedure for this. Only in this case can Arizona, through either law or regulation require someone to verify their citizenship.
3. The third method of federal voter registration is mandated
by Section 5, § 1973gg-5, which requires states to designate
certain state offices for voter registration. Targeting “the poor
and persons with disabilities who do not have driver’s
licenses and will not come into contact with” motor vehicle
agencies.
Lastly the Help America Vote Act of 2002 PL 107-252 defines how a person who is registering for the first time can establish their identity.
HAVA requires any voter who registers to vote by mail and has not previously voted in a Federal election show current and valid photo identification or a copy of a current utility bill, bank statement, government check, paycheck, or other government document that shows the name and address of the voter.
The proposed law from Arizona is in violation of the Voter Rights Act, the National Voter Registration Act and the Help America Vote Act. As a result, the decision to remand specific parts of the proposed Arizona law is appropriate.
Now my personal opinion: I think that anyone registering to vote in Federal Elections should be required to establish their citizenship or eligibility to vote. I think that is a reasonable expectation from the government.
That means that the appropriate procedure is to introduce in Congress a bill that modifies the VRA, NVRA, and HAVA. It is not permissible for one state to unilaterally decide whether they will or will not follow federal law and federal regulations.
There is a correct way to do this, and Arizona chose the wrong way.
So this decision has nothing to do with politics, it is not a liberal/conservative/Democrat/Republican issue at all. It is a legal issue and Arizona failed to follow the law.