If the GOP gains control of Congress and prioritizes mass deportation, state resistance could still be significant, especially in sanctuary states and cities. State and local resistance would likely limit the reach of mass deportation, even if there is support from a GOP-controlled Congress. State autonomy protections, community policing priorities, logistical barriers, and potential legal pushback would likely slow, limit, or reshape the federal government's ability to implement a widespread deportation agenda. States like California, New York, and Illinois could still legally challenge federal deportation mandates, arguing that mass deportation violates state autonomy and that compelling states to enforce federal immigration policies breaches the Tenth Amendment.