Although sanctuary policies violate Federal law, two states (Maine and New Mexico) and a multitude of cities and counties maintain such policies
that forbid officials from asking about a person's immigration status or informing Federal immigration authorities about the presence of illegal aliens.
These sanctuary policies may prevent police from inquiring about a person's immigration status during the course of routine duties, or from stopping or detaining a person solely due to immigration status. They may also prevent state public assistance agencies and institutions of higher education from inquiring about an applicant's immigration status in order to determine eligibility for public benefits. The resulting safe havens make it easier for illegal aliens, including criminal aliens, to live undetected in the United States.
Sanctuary policies directly violate Federal law. Section 642 of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA) provides that "[s]tates and localities may not adopt policies, formally or informally, that prohibit employees from communicating with DHS regarding the immigration status of individuals. However, neither DHS nor the Department of Justice (DOJ) has ever challenged a sanctuary policy. Soon after IIRIRA was passed, the City of New York challenged this provision in court. When the court upheld the law and ordered the city to rescind its sanctuary policy, the city responded by modifying it – but only slightly. Subsequently, DOJ has declined to challenge the new sanctuary policy.
Sanctuary policies also hinder the ability of police to combat increasingly violent criminal alien gangs like MS-13. Such gangs engage in murder as well as the trafficking of drugs and illegal aliens. There are indications that MS-13 may be cooperating with al-Qaeda in smuggling potential terrorists and/or weapons across the border.
On October 8, 2007, the Phoenix Law Enforcement Association, a union representing more than 2,200 officers and detectives in the Phoenix Police Department, called for an end to sanctuary policies in their area. An article in the Arizona Republic quotes Mark Spencer, the union's president, as saying, "If we allow a little bit of lawlessness, what prevents more lawlessness from occurring." Spencer wants to end the city's sanctuary policy because it makes streets more dangerous for police officers and civilians alike.