The issue focused on border enforcement and enforcement of immigration laws. Law enforcement officers made illegal immigrant arrests as part of their enforcement duties. Critics accused police of illegally stopping people at checkpoints and illegally detaining them for immigration enforcement purposes. Law enforcement officers argued that illegal immigrant arrests were legitimate police enforcement activities and legal under federal law. Law enforcement officers claimed that illegal immigrant arrests were legitimate police enforcement activities and legal under federal law. Law enforcement officers argued that illegal immigrant arrests were legitimate police enforcement activities and legal under federal law. Law