Modus Vivendi

Modus vivendi, or modus operandi refers to a provisional, informal, political agreement between those who differ in opinions (‘agreeing to disagree’). By such agreement, two contending parties establish a communication channel and agree to avoid further escalation without prejudice to eventual settlement of the conflict. It might serve to temporarily settle claims to a disputed territory (for example in situations of overlapping maritime claims) or as a means to establish relations with a party the legal personality of which is questioned despite the factual circumstances to the contrary.

Traditionally, the term is also used in armed conflict where the ceasefire or the armistice agreements only provide for an end to the hostilities, but do not settle the full range of interests between the parties. They also help accommodate the commitments taken vis-à-vis non-state actors, as for example in the Armed Activities on the Territory of the Congo (Uganda) case (at para 99).

Modus vivendi is not meant to create legal obligation, but to respond to the interests of the parties to maintain the status quo until further settlement by agreement or an authoritative judgment can be achieved. A quintessentially unperfected international legal act as described by Riesman (2002, p. 738), it stays in force and relevant as long as the parties comply with its provisions. In other words, by not complying to the terms of the modus operandi, the parties risk returning to the unregulated stage of the suspended conflict with an even smaller chance of agreement, less trust, and, consequently, more limited prospects of settling the conflict peacefully.

Modern modus vivendi or modus operandi agreements are rarely signed and rather consist of mutually accepted unilateral declarations, establishing certain understandings or rather defining disagreements and creating certain rules of operation in order to avoid the conflict (see 1954 Delhi statements on Panchsheel, 1994 Bishkek Protocol on Nagorny Karabakh ceasefire, 2003 India-Pakistan ceasefire).

One China policy and law

The United States moved to recognise the People’s Republic of China and de-recognise the Republic of China from 1 January 1979 by adopting the joint ‘Normalization Communique’ on 15 December 1978, which included, inter alia, a commitment to establish diplomatic relations.

There was no clear indication of the further status of Taiwan: the United States of America recognised the Government of the People’s Republic of China as the sole legal Government of China. The sole assurance of the political independence of the island was the reference to the fact that ‘the people of the United States will maintain cultural, commercial, and other unofficial relations with the people of Taiwan.’

The Government of the United States merely acknowledged in a 1978 communique the presence of the Chinese position that there is but one China and Taiwan is part of China. The subsequent bilateral 1982 communique did elaborate slightly that the United States has no intention of pursuing a policy of ‘two Chinas’ or ‘one China, one Taiwan’; however, it did not recognise Chinese sovereignty over the island. It would be fair to note that the 1982 understanding also includes US commitment not to carry out a long-term policy of arms sales to Taiwan. Numerous meetings thereafter reiterate the United States adhesion to its ‘One China’ policy and the principles set forth in the US-China joint communiques. The ‘One China’ policy has subsequently been reaffirmed by every new incoming US administration.

As for the commitments to Taiwan, the Taiwan Relations Act of 1979 (P.L. 96-8) stipulates the expectation that the future of Taiwan ‘will be determined’ by peaceful means. It further specifies that the US will consider any non-peaceful means to determine Taiwan’s future ‘a threat’ to the peace and security of the Western Pacific and of ‘grave concern’ to the United States, will ‘provide Taiwan with arms of a defensive character’, and will ‘maintain the capacity of the United States to resist any resort to force or other forms of coercion’ jeopardising the security, or social or economic system of Taiwan’s people.

On the other hand, the People’s Republic of China has never renounced its sovereignty claim. The Anti-Secession Law of 2005 sets forth three conditions under which China would be justified in using ‘non-peaceful means and other necessary measures to protect its sovereignty and territorial integrity’: 1) if Taiwan independence forces cause Taiwan’s secession from China; 2) if major incidents entailing Taiwan’s secession from China occur; or 3) if possibilities for peaceful reunification are completely exhausted.

Commitment to abstain?

It appears that existing bilateral commitments preclude forceful annexation of Taiwan in exchange for guarantees of non-recognition of the statehood of the Republic of China. However, these are not the documents governing the use of force in international relations. The legal consequences of this status quo are to be considered in the light of international law and practice.

The existing situation cannot be interpreted having created legal effects of both recognising the sovereignty of the People’s Republic of China over the island or vice versa, recognising Taiwanese independence. Temporary modus vivendi agreements, including the one incorporated in the communiques quoted above, do not, by definition, create international legal obligations.

Neither can they be interpreted as subsequent State practice regarding interpretation of another existing agreement. According to the draft conclusions of the International Law Commission, positions regarding interpretation of international law cannot be established if the parties have merely agreed to establish a practical arrangement. In other words, temporary arrangements, important as they are for the normalisation of relations between States and peaceful settlement of a conflict, might not and will not amount to opinio juris. This latter subjective element of customary international law is the determining factor of a legal norm from a mere practice. The universal conviction that the non-compliance with a certain practice will result in international responsibility is one good indicator of opinio juris.

The question arises thus in relation to the statement of the US President confirming the commitment to come to Taiwan’s defence. Asked if the United States would commit to protect Taiwan in the event of a war, Biden appeared to respond affirmatively: ‘Yes. We have a commitment’. Did President Biden misspeak, in the light of the quick clarification of the White House that there was no change in policy? Hardly.

Although a State may decide not to recognise a de facto State, which controls its own territory effectively, it cannot deny that it possesses certain rights and duties under international law. Without expanding into a detailed analysis or repeating what has already been extensively written elsewhere, it is important to underline in this respect that the territory of Taiwan has never been under the control of the People’s Republic of China. The prohibition of the use of force is enshrined in Article 2(4) of the UN Charter, which is a norm of not only customary international law but also jus cogens. It is accepted and recognised as a norm from which no derogation is permitted. Jus cogens or peremptory norms are considered to have acceptance among the international community of States as a whole. Under the Vienna Convention on the Law of Treaties (Article 50), any treaty in violation of a peremptory norm is void, even if considered as creating international legal obligations by its parties.

Pacta sund servanda norm remains the core of international law. Respecting bilateral agreements contributes to global peace and security and as such serves the whole international community. The exact content of a bilateral commitment, however, must be determined in application of the whole range of existing and constantly developing rules. Can bilateral understanding on ‘One China’ policy replace the prohibition of the use of force? Does the non-recognised (or rather de-recognised) status of Taiwan mean PRC has acquired sovereignty over the island? Even if China refuses to discuss the legal aspects of its claim, they remain nevertheless important. So far – academically.