Final answer:
Numerous sanctuary cities have chosen not to detain undocumented immigrants for ICE, leading to threats of federal fund withholding. This reflects the tension between federal and state authority over immigration policies, exemplified by laws like Arizona's SB 1070 and Supreme Court rulings affirming federal supremacy in immigration matters.
Step-by-step explanation:
Numerous sanctuary cities, which are primarily large urban areas, have adopted policies of not cooperating with immigration officials by refusing to detain undocumented immigrants for U.S. Immigration and Customs Enforcement (ICE). Consequently, these cities have faced threats from the federal government of the withholding of federal funds for their lack of compliance. This issue highlights the complex interplay between federal and state powers when it comes to immigration policies. In recent history, states have passed strict immigration laws, like Arizona's SB 1070, in efforts to regulate the residency of undocumented immigrants, leading to societal division and significant legal challenges.
Decisions like the Arizona v. United States case by the Supreme Court reaffirmed the federal government's supremacy in immigration matters. Despite the conflicts, some states, such as California during the COVID-19 pandemic, have taken measures to support undocumented immigrants by providing financial aid to those who are ineligible for federal programs. The polarized views on immigration law enforcement and the rights of immigrants underline the ongoing debate over how to balance the enforcement of immigration laws with civil liberties and humanitarian concerns.