Some of the situations laid forth by Hübner are not so much regulated by the duties of neu-trality as they describe conditions needed for neutrals to be able to respect their duties. The seventh situation of the first list establishes that in order to enjoy the prerogatives connect-ed to a legal status of neutrality, it is just and necessary that this status is duly demonstrat-ed.89 This situation rests more on formal requirements than on one of the cornerstone-duties of neutrality. Hübner explains that it is a neutral merchant vessel’s duty to be able to prove the veracity of its claim to neutrality. This means that someone who claims to be neutral must be able to prove by suitable documentation that he truly is in the position to claim the right to the privileges in question; otherwise he will only be exposed to the inconveniences of war.90 Belligerents can legitimately capture neutral ships whose papers are not in order or who lack any tangible or reasonable evidence of their neutrality. They have the right to stop neutral ships in an “appropriate manner”, until the necessary information has been procured to be able to judge them. However, belligerents are required to release them when it is proven that they truly are neutral and that they have acted accordingly. Nevertheless, the neutral ships are not entitled to any compensation for the delay of their navigation, or the potential costs incurred by the procedure, because they are themselves responsible for the mix-up. Although this seems a little strict, it corresponds with Hübner’s strict and abso-lute rules of neutrality.
The seventh situation of the second list addresses the issue of territorial jurisdiction by es-tablishing a geographical outline of capture. This case simply states that neutral ships can-not be captured when they are in the bays, ports or within the cannon-range of their own country or that of another neutral nation. This case relates to the issue of territorial mari-time jurisdiction and sovereignty. A sovereign nation has no reason to suffer the intrusion of foreigners visiting ships docked in its bays and ports and within reach of its cannons.
ships from places under local jurisdiction. From this chain of reasoning Hübner deduces that there is no reason that permits them to act similarly towards neutral ships in neutral harbours. These ships are under the transient jurisdiction of the local sovereign. Ships be-longing to neutral nations, staying in the harbours or within reach of the cannons of another equally neutral nation cannot be visited or seized by a belligerent. The matter is easily re-solved by a general rule: the ultimate right of command belongs only to the legitimate and actual sovereign of the area, consequently no one can exercise any act of authority without the express or tacit permission of the local sovereign. This equally applies for natural har-bours that often serve as places of shelter and repose during difficult weather conditions and long journeys. Consequently, ships that take shelter anywhere along the coastline of a neutral nation are under the protection of the local sovereign. Although it might be difficult to ascertain with precision the extent of maritime boundaries, Hübner maintains that it is generally believed to extend at least to the reach of artillery91, which the sovereign is al-ways at liberty to use to warn those who forget their place and violate the rights of others.
In the eighth situation of the second list Hübner addresses the legal timeframe of capture.
In this case, Hübner maintains that the main rule is that neutral ships cannot be captured before a formal declaration of war. The same reasons that speak for the importance of rec-ognised and public neutrality also speak for the importance of being able to distinguish belligerent nations as such. The state of war must be sufficiently known and declared so that those who wish to stay at peace have the possibility of observing the obligations that follow their neutral status. Although declarations of war are an imperfect right for the ag-gressed party and that this right is derived from the customary law of nations, it remains of great importance for the neutral nations. Hübner says that a formal declaration of war is
“necessary” for neutral nations because it is only fair that they should be instructed so that they may implement the necessary measures concerning their maritime commerce and nav-igation and concerning the execution of alliances or neutrality treaties with some of the belligerents that they might already be bound by. Belligerent nations cannot expect neutral
nations to observe the laws of neutrality unless they are sufficiently and authentically in-formed of the outbreak of war. This is essential because it was often difficult in the 17th and 18th century to distinguish between actual hostilities related to war and simple reprisals that could be significant without leading to outright conflict. Neutral nations could also consider such events to be apocryphal and suspect since they have not been authentically and for-mally declared.92 Neutrality is always relative to the state of war and the neutrals can only know the reality of such a status by the means of a formal and authentic declaration of war by those who enter into that state. However, the form of the declaration is less important provided that it is not ambiguous and that it is communicated to neutral nations through sure and accredited channels. Furthermore, in order to trigger the duties of neutrality, it is enough that one of the belligerent parties declares its intentions. Vattel also states that the one who is attacked and wages a defensive war need not make any formal hostile declara-tion.93
The second list’s ninth situation concerns the case of general truce between belligerent powers and also broaches the issue of a legal timeframe for capture. A general truce con-sists of an absolute cessation of the hostilities or effects of war and does not, for the sake of the neutrals, differ from a state of peace other than by its time-limitation. It is different in the case of a particular truce limited to a place or a certain kind of military activity. Since the war and its consequences continue as before elsewhere and in relation to everything else, such a truce would not change the duties of neutrals, nor the belligerents right to cap-ture (at least elsewhere then the implied areas of the particular truce).