Please tell me what law(s) on the federal level say a person can be questioned by police on "suspicion" of being an illegal alien.


A police officer can question anyone they want who they suspect has commited a crime.


The percentage of Arizona voters in favor of the law makes no difference to me. A similar percentage of the populations of Mississippi
and Arkansas in the early 1960s probably favored segregated schools. One of the roles of the federal government is to hold the rights
of citizens. We do not live by mob rule.


70% isn't a mob. It's a majority.

Your anology of segragation isn't applicable, as the blacks were American citizens being denied their rights. This is an issue of
people who are NOT citizens, and therefore do not have civil rights. These are two entirely different situations.