The 9th Circus got it wrong.
The Supremes got it right.
The argument against voter ID was that it violated the 24th Amendment to the US Constitution. They said it would amount to a "poll tax", requiring people to pay for an ID to prove residency.
For clarification, here's the text of the 24th Amendment:
Section 1. The right of citizens of the United States to vote in any primary or other election for President or Vice President, for electors for President or Vice President, or for Senator or Representative in Congress, shall not be denied or abridged by the United States or any State by reason of failure to pay any poll tax or other tax.
Now in order to invoke a violation of the 24th Amendment, the aggrieved person first has to show that they are a CITIZEN.
And how do they do that?
By showing proper identification. The same thing that Arizona requires at the polls in order to vote.
The fight against the Arizona Law was nothing more that an attempt to continue to allow immigrants, legal (not yet citizens) and illegal, to vote. The action was filed by the ACLU and other liberal groups, since illegal and legal immigrants fall predominently on the left. (Democrat)
Think about it. Voting is the most important and powerful thing we can do in our lives. You need a photo ID to rent a movie from Blockbuster, but those morons don't think we need one to vote?