Final answer:
The false statement about immigration federalism is that the Arizona v. United States decision struck down all of Arizona's restrictive provisions, whereas only certain parts were struck down, while some were upheld. Policies on undocumented immigration have seen significant changes and have been a point of contention at both state and federal levels.
Step-by-step explanation:
The statement about immigration federalism that is false is that the Arizona v. United States decision struck down all of Arizona's most restrictive provisions on undocumented immigration. In reality, the Supreme Court in 2012 struck down several provisions in Arizona's law but upheld the authority of police to ascertain the immigration status of someone they suspect of being an undocumented immigrant if the person had been stopped or arrested for other reasons.
Further, policies regarding undocumented immigration have evolved over time. During the 1980s, the surge in undocumented immigration led to the Immigration Reform and Control Act of 1986, requiring employers to verify employee eligibility. Recent debates have focused on the balance of state and federal powers, such as in the U.S. v. Texas case, and public opinion has shown support for providing undocumented immigrants with a path to citizenship under certain conditions.