Dozens of people, including members of the Coalition for Humane Immigrant Rights of Los Angeles as well as the American Civil Liberties Union, gathered on the steps of City Hall to protest one provision of the law that the court upheld. Protesters called the ruling "disgraceful."
The provision allows police to check the immigration status of people they stop if officers have reasonable suspicion that they are in the country illegally.
"Over time, we will be able to demonstrate that there is no way to implement this provision without discriminating, without profiling, without violating the constitutional rights of the people involved," Villaraigosa said.
LAPD Chief Charlie Beck also spoke out against the law. Los Angeles' Special Order 40 prevents officers from using immigration as a primary reason to question someone.
"Certainly in L.A., if we were mandated to take action every time we suspected somebody of being an undocumented immigrant, it would totally flood our system. We would be unable to do anything else," Beck said.
Arizona's law has been controversial from the beginning. Immigration supporters are pledging not to give up the fight until the entire law has been struck down.