a) The expression of free consent
the
Vienna Convention which governs agreements concluded in written form between States, confirms in its Article 6 that every State possesses capacity to conclude treaties. The will of a State finds its expression through persons who are authorized to do so or who are considered to be state representatives.
Since international treaty law in its entirety is subject to the
free consent principle. it is quite logical that the
Vienna Convention offers a broad choice of possibilities to express consent (Article 11), i.e.
- signature,
- exchange of instruments constituting a treaty
(in the case of bilateral treaties this often happens through the
exchange of notes),
- ratification,
- acceptance,
- approval,
- accession or
- by any other means if so agreed.
A typical clause of entry into force can be found in Article 84 of the
Vienna Convention itself which reads:
"
1. The present Convention shall enter into force on the thirtieth day following the date of deposit of the thirty-fifth instrument of ratification or accession.
2. For each State ratifying or acceding to the Convention after the deposit of the thirty-fifth instrument of ratification or accession, the Convention shall enter into force on the thirtieth day after deposit by such State of its instrument of ratification or accession."The States Parties - primarily the contracting States (see Article 2 (1)(f)) - can also agree to apply a treaty provisionally pending its entry into force (Article 25). This agreement can be laid down in the treaty itself or in another way. If this done in the treaty itself, the agreement enters into force with its signature (and which in this case remains, of course, subject to ratification).
For reasons to be found in their own domestic legislation it is not possible for some States - Austria, for instance - to apply international conventions provisionally.
Finally, it should be mentioned that there are constitutions like that of Portugal (see
Artikel 8) which do not authorize States to express their consent through all of the means enumerated in Article 11 of the
Vienna Convention; hence, for Portugal there is only a possibility to ratify or approve a treaty. Since this is the result of a domestic provision, a consent which would be expressed in a different manner would not be flawed from point of view of international treaty law, because the ways and means to express consent are already determined by customary international law and not only by the
Vienna Convention to which, by the way, Portugal is not a party.
