The INA is the statute that allocates immigration authority between Congress, the executive branch, and the states. It defines every status category in the modern system — citizen, lawful permanent resident, nonimmigrant visa holder, parolee, asylum seeker, refugee, and the grounds that make someone deportable or eligible for relief. It gives federal agencies exclusive control over admissions, detention, removal, and work authorization, and it limits what states and cities can do, even when they try to regulate indirectly through licensing or policing. Enforcement structures — from Border Patrol to asylum offices to immigration courts — all operate under this statute. Nearly every immigration outcome turns on how the INA classifies a person and what powers it grants federal officials over that classification.

The Refugee Act sets the legal framework for who qualifies as a refugee and how the United States admits and resettles displaced people. It creates the statutory definition of “refugee,” builds the asylum system inside the INA, and establishes the president’s authority to set annual admissions ceilings with congressional consultation. It assigns federal agencies control over screening, vetting, and placement while limiting state authority to block or override resettlement. It also structures the benefits and services refugees receive during their first years in the country. Modern enforcement — from credible fear interviews to asylum grants and denials — flows directly from the categories and standards created here.

IRCA reshaped the system by creating both a path to legal status for millions of undocumented residents and the country’s first nationwide employer-sanctions regime. It granted the federal government authority to regulate workplace verification (the I-9 process), imposed penalties on employers who hire unauthorized workers, and formalized the distinction between authorized and unauthorized status in employment. It did not give states the power to add their own penalties or parallel enforcement systems, which is why most state-level immigration crackdowns get struck down. IRCA also created new status categories through legalization and tightened the rules for future status adjustments. Today’s workplace enforcement, E-Verify debates, and employer liability all trace back to this statute.