Section 3 (state crime for failure to carry federal immigration registration documents)

      The Supreme Court struck down §3, which sought to create a state crime for not carrying immigration papers.  The Court invalidated Sec. 3 on the grounds that it adds a state-law penalty for conduct already regulated by federal law.  The Court explained that the federal government is responsible for maintaining a system to keep track of non-citizens within the U.S. If §3 were valid, every State could give itself independent authority to prosecute federal registration violations and that would diminish the federal government's control over enforcement. 

Section 5(C) (state crime for unauthorized work by immigrants)

·      The Supreme Court also struck down Sec. 5, which sought to make it a state crime for a non-citizen to work without authorization.  Again, the Court pointed to the fact that the federal government already regulates employment by non-citizens and decided not to impose criminal penalties for unauthorized work.  The Court ruled that "Under §5(C) of S. B. 1070, Arizona law would interfere with the careful balance struck by Congress with respect to unauthorized employment of aliens."  

Section 6 (authorization for local law enforcement to arrest individuals without a warrant for a removable offense)

 ·      The Supreme Court also struck down Sec. 6, which sought to give state and local police officers greater power than federal officers to arrest immigrants they believe are removable from the U.S.  The Supreme Court ruled that such a law would allow Arizona to achieve its own immigration policy and that "this is not the system Congress created."  Slip Op. at 17.  The Court concluded that "§6 violates the principle that the removal process is entrusted to the discretion of the Federal Government." 

Section 2(B) (mandate for local law enforcement to determine immigration status of any detained person reasonably suspected of being undocumented)

      The Supreme Court decided that it was too early to block Section 2B, which requires state and local officers to make a reasonable attempt to determine the immigration status of any person they stop, detain, or arrest if reasonable suspicion exists that the person is an alien unlawfully present in the United States. 

      However, the Supreme Court warned that "Detaining individuals solely to verify their immigration status would raise constitutional concerns."  Slip Op. at 22. 

      The Court stated that "if §2(B) only requires state officers to conduct a status check during the course of an authorized, lawful detention or after a detainee has been released, the provision likely would survive . . ."  Slip Op. at 23. 

      The Court ruled that because "There is a basic uncertainty about what the law means and how it will be enforced," the state courts should give an interpretation of the law. 

      The Court made clear that "This opinion does not foreclose other preemption and constitutional challenges to the law as interpreted and applied after it goes into effect."  Slip Op. at 24.

Source:  MALDEF