Treaties — Conclusion and operation — Constitutional limitations — Ministerial decree in conflict with provisions of prior enacted international treaty — Whether decree binding on municipal courts — Article 66 of Dutch Constitution — The law of the Netherlands

State territory — Parts of — Rivers — International rivers — The principle of freedom of navigation on international rivers — Restrictions in the interests of general security — Reasonableness test — Act of Mannheim, 1868, Article 1 — Re-routing of inland shipping for benefit of seagoing traffic — Whether ministerial decree which violates prior international treaty may be applied by the municipal courts — Article 66 of the Dutch Constitution — The law of the Netherlands