Article 13 provides specific safeguards to protect aliens lawfully present in a State in proceedings for their expulsion: their expulsion must be pursuant to a decision reached in accordance with law; they must be allowed to submit reasons against their expulsion; they may have their case reviewed by a competent authority (or designee); and they may be represented for that purpose. The qualification ‘except where compelling reasons of national security otherwise require’ applies to all but the requirement that the decision must be reached in accordance with law. It operates as a limitation provision. When a State relies on it the compelling reasons asserted will be subjected to strict scrutiny.