3 Table of Contents Acronyms ...................................................................................................................................................... 4 Introduction .................................................................................................................................................. 5 1. Who is detained? ....................................................................................................................................... 7 2. What is the detention system? .................................................................................................................11 3. What legal frameworks govern detention? ............................................................................................ 14 4. How do politics shape detention? ........................................................................................................... 19 5. How long are migrants detained? .......................................................................................................... 23 6. What are the conditions for migrants in detention?............................................................................. 25 7. What is “de facto” detention? ................................................................................................................ 30 8. How do migrants challenge detention? ................................................................................................. 35 9. What alternative approaches exist to replace detention? .................................................................... 38 Conclusion .................................................................................................................................................. 40 Immigration Detention Across Borders Detention of Asylum Seekers in the United States and the European Union