( CNN ) -- A coalition of civil rights organizations has filed a motion in federal court seeking to block an Arizona law that requires officers to make immigration checks while enforcing other laws if `` reasonable suspicion '' of illegal immigration exists . The so called `` show me your papers '' provision is perhaps the most controversial aspect of Arizona 's tough immigration law , SB 1070 . The U.S. Supreme Court last month , in response to a challenge by the Justice Department , struck down three provisions of SB 1070 , but upheld the police immigration checks . The civil rights groups asked the court to block implementation of the law while they make their case that the provision is unconstitutional . Even though the Supreme Court upheld the provision , the civil rights organizations say they are presenting new arguments and new evidence against it . In the motion , the organizations argue that the provision in question will result in extended detentions while statuses are being checked , violating the Fourth Amendment protections against unreasonable searches . The motion also argues that the provision violates the Equal Protection Clause because `` racial or national origin discrimination was a motivating factor in its enactment . '' It also calls for an injunction to another part of SB 1070 that makes it a state crime to harbor immigrants who are in the country illegally . `` In a state that 's more than 30 percent Latino , requiring police to act as immigration agents is an invitation to racial profiling on a massive scale , '' Omar Jadwat , a senior staff attorney with the ACLU Immigrants ' Rights Project , said in a statement . `` Police chiefs and communities know these laws do n't work , and we hope that the courts will continue to block them from going forward . '' According to the ACLU , the new evidence shows that lawmakers who supported SB 1070 used false statements and discriminatory language with the intention to impose a statewide practice of racial profiling . The motion was made on behalf of plaintiffs in Valle del Sol v. Whiting , et al. , a class action lawsuit challenging SB 1070 , filed in May 2010 . In addition to the ACLU , those presenting the motion include the National Immigration Law Center , the Mexican American Legal Defense and Educational Fund , and the National Day Laborer Organizing Network . Earlier this month , federal officials said they had not seen a change in the number of illegal immigration checks sought by local Arizona police as allowed by the partially upheld law . The Phoenix Police Department and at least two sheriffs in Arizona told CNN that the law wo n't result in great change for their departments . But Tucson Police Chief Roberto Villasenor expressed concern in an interview after the ruling about whether his 950-officer agency has been dealt an `` impossible mandate . '' The state law allows citizens to sue his department or others if they fail to enforce federal immigration laws , the chief said . `` Just for my agency , it will be a huge workload , just making the calls and waiting for a response on what to do , '' the police chief of Arizona 's second-largest city said . `` I 'm not sure the federal government is capable of handling all the requests that they will be receiving , '' Villasenor added . `` I do n't know what effect it will have on my agency . ''
A coalition of civil rights groups wants to block parts of Arizona 's immigration law . The group says the measure would allow police officers and other government workers in Arizona to ask about a person's legal status if they suspect that person is here illegally. There are new arguments and evidence that SB 1070 is unconstitutional , the motion says .