The ACLU and the ACLU of Michigan are in federal appeals court today, in a challenge to the FBI's refusal to make public information about which American communities it's spying on. The argument comes in a lawsuit we filed in 2011 , after the FBI refused to respond to our request for information about the implementation of its racial and ethnic mapping program in Michigan. (Read more about the case here .)

Documents obtained by 34 ACLU affiliates in a coordinated public records request revealed that the FBI spies on entire racial and ethnic communities based on nothing more than stereotypes it ascribes to certain minority groups. Using public source information, including U.S. census data, it creates maps of these racial, ethnic, and national origin communities – even if none of them have been suspected of wrongdoing. Targeted groups include Muslims and Arab-Americans in Michigan, African-Americans in Georgia, Chinese and Russian-Americans in California, and broad swaths of Latino-American communities in multiple states.

This much we know. But the FBI continues to keep secret critical information — like its use of U.S. census data — that would tell us how many communities it is targeting and which ones. And the FBI is also asking courts to use a one-sided, secret judicial process to decide whether it can keep information secret by relying on a Freedom of Information Act provision that allows government agencies to avoid confirming or denying the very existence of requested records. This undermines the principles of transparency and public access at the foundation of our judicial system, along with the purpose of the FOIA to promote government transparency and accountability.

This lawsuit is part of our effort to push back against the vast expansion of FBI authority to engage in unlawful and abusive surveillance of innocent Americans in the years since 9/11. Our " Mapping the FBI " initiative is working to expose misconduct, abuse of authority, unconstitutional profiling, and other violations of Americans' rights and liberties across the country.

In a separate constitutional challenge to discriminatory surveillance, the ACLU sued the New York Police Department last month over its systematic, suspicionless surveillance of Muslim New Yorkers. Our clients knew they were subjected to the discriminatory program, but the broader public found out the sweeping extent of it as a result of reporting by the Associated Press in 2011. For the public to know how the FBI is targeting entire Michigan communities for racial or ethnic profiling, we needs the facts – and the Freedom of Information Act exists in order to facilitate our access to them. We hope the judges of the Sixth Circuit agree.