Schengen is now a core part of EU law, and all EU member states without an opt-out which have not already joined the Schengen Area are legally obliged to do so when technical requirements have been met.
Dabar Šengenas yra ES teisės dalis ir visos Europos Sąjungos šalys, kurioms nepadaryta išlyga, yra įsipareigojusios prisijungti prie Šengeno erdvės, kai tik atitiks techninius reikalavimus.