Owing to the lack of consensus in formal negotiations, unilateral statements do not create legal obligations on states. Thus, a unilateral statement is not considered a source of international law under Article 38 of the Statute of the International Court of Justice. In practice, however, these statements can be legally binding on the states making them and play an important role in the development of international law. The paper aims to examine the characteristics of unilateral declarations and statements in international law and address the Vietnam’s position over the legal effects of the Diplomatic Note 1958 with special references to the South China Sea dispute. This paper will analyze the characteristics and significance of unilateral statements in international law, and argue the conditions for legal binding force. Finally, this paper will provide an in-depth clarification on Vietnamese position on the legal effect of the Diplomatic Note 1958.

I. Introduction
II. Characteristics of Unilateral Statement
III. Types of Unilateral Statement
    A. Declaration of Independence
    B. Declaration of State/Government Recognition
    C. Declaration of Commitment
    D. Declaration to Waive Sovereignty
    E. Declaration of Objection
    F. Declaration of Maritime Sovereignty
    G. Statements to Accept the ICJ Jurisdiction
IV. Significance of Unilateral Statement
    A. The Expression of a State’s Position on International Relations
    B. The Creation of Legally Binding Obligations
    C. A Circumstances for Estoppel
    D. The Creation of Customary International Law
V. Conditions for Legal Binding Force of UnilateralStatement
    A. The statement must be made by the state’s competent authorities.
    B. A clear, open statement and the contents must convey the consentto be bound.
    C. It should be accepted by the states concerned.
    D. It can be either verbal or written in form.
    E. It should be given to a specific state, to some countries, or theinternational community at large.
    F. It is not contrary to the peremptory obligations under internationallaw.
VI. The Vietnamese Position to the Diplomatic Note 1958
VII. Conclusion

• Tran Thang Long(Associate Professor of International Law at Ho Chi Minh City University of Law, Vietnam. B.A./LL.M.)