The Supremacy Clause of the Constitution is what it is. The judge ruled, and the 9th Circus agreed, that what Arizona did, violates the Constitution.
We can agree on the absence of effective federal action; it's more a question of addressing them in ways that don't violate the Constitution.
It will be helpful for you to understand that no court has yet made a final decision as to whether the AZ law violates the Constitution.
The judge, Susan Bolton, did not so rule. Her preliminary injunction is based only on her belief there is a “likelihood” of unconstitutionality. Bolton expressed concern the government would likely suffer irreparable harm should enjoined provisions of the law take effect.
For instance, she believes that harm includes such things as an increase in requests for immigration status determination that will overtax federal resources. Further, notwithstanding federal law that federally-issued immigration documents be carried at all times, that the workload of federal officials would be increased because they do not now enforce that law.
Those are "cry me a river" concerns and meanwhile, of course, AZ bleeds both red and green on a daily basis.
The 9th, after wringing its hands that our foreign policies would be damaged, merely held that Bolton did not abuse her discretion by enjoining SB1070; it did not otherwise rule on anything.
You and I may agree on one thing: WTH is Congress on this issue?
Lets be sure to talk again in a few months.