Arizona does have the right. Obama (and the Bushes, and Clinton...) did not and are not doing their job. Power-hungry politicians want more illiterate illegal aliens as voters, knowing that most will become Democrats. Amnesty is coming to accomplish that. Employers want cheap labor. Those are some reasons why no administration wants to enforce even existing laws.
What I don't understand is why a lot of states don't boot the Feds out. The County Sheriffs have the power, if they were willing to use it, to boot out Federal agents.