Final answer:
U.S. law targeting non-citizen gang members is complex, involving state and federal statutes with Arizona's SB 1070 being partially invalidated by the Supreme Court. The Secure Fence Act of 2006 and 1986 laws also address illegal immigration, employment, and border security measures.
Step-by-step explanation:
In an effort to regulate illegal immigration, the U.S. has passed several laws targeting non-U.S. citizens involved in gang activities and those who are in the country illegally. One notable piece of legislation is Arizona's state law, known as SB 1070, which was partially struck down by the U.S. Supreme Court in Arizona v. United States. Previously, the U.S. also debated federal measures that would make unauthorized entry a felony and impose penalties on individuals aiding undocumented immigrants, but these attempts failed to be codified into law.
The Secure Fence Act of 2006 received bipartisan support and led to the construction of barriers along the U.S.-Mexico border. Meanwhile, the 1986 law established penalties for employers hiring unauthorized aliens and provided a guest-worker program. Immigration reform continues to be a contentious issue, with proposals like the “DREAM Act” offering potential paths to citizenship for certain undocumented immigrants brought to the U.S. as children, failing at the federal level but finding success in individual states like California.