DUAL JURISDICTION OF THE ICJ

The International Court of Justice acts as a world court.
The Court has a dual jurisdiction :
it decides, in accordance with international law,
disputes of a legal nature that are submitted to it by States
 (jurisdiction in contentious cases);
and it gives advisory opinions on legal questions
at the request of the organs of the United Nations
or specialized agencies authorized to make such a request
 (advisory jurisdiction). 

Contentious Jurisdiction

In the exercise of its jurisdiction in contentious cases, the International Court of Justice
 has to decide, in accordance with international law, disputes of a legal nature
 that are submitted to it by States. An international legal dispute
can be defined as a disagreement on a question of law or fact,
a conflict, a clash of legal views or of interests.
Only States may apply to and appear before the International Court of Justice.
 International organizations, other collectivities and private
persons are not entitled to institute proceedings before the Court.
Article 35 of the Statute defines the conditions of access for States
to the Court. While paragraph 1 of that Article
 opens it to the State parties to the Statute, paragraph 2
 is intended to regulate access to the Court by States
which are not parties to the Statute. The conditions
 of access of such States are, subject to the special provisions
contained in treaties in force at the date of the entry into force
 of the Statute, to be determined by the Security Council,
with the proviso that in no case shall such conditions place
the parties in a position of inequality before the Court.
The Court can only deal with a dispute when the States
concerned have recognized its jurisdiction. No State
can therefore be a party to proceedings before the
Court unless it has in some manner or other consented thereto.

Advisory Jurisdiction

Since States alone have capacity to appear before the Court, public (governmental)
 international organizations cannot as such be parties to any case before it.
A special procedure, the advisory procedure, is, however, available
to such organizations and to them alone.
Though based on contentious proceedings, the procedure
in advisory proceedings has distinctive features resulting from t
he special nature and purpose of the advisory function.
Advisory proceedings begin with the filing of a written request
for an advisory opinion addressed to the Registrar by the
United-Nations Secretary-General or the director
or secretary-general of the entity requesting the opinion.
In urgent cases the Court may do whatever is necessary
to speed up the proceedings. In order that it may be
fully informed on the question submitted to it, the Court is
empowered to hold written and oral proceedings.
A few days after the filing of the request, the Court
draws up a list of those States and international
organizations likely to be able to furnish information
on the question before the Court. In general, the
 States listed are the member States of the organization
 requesting the opinion, while sometimes the other states
to which the Court is open in contentious proceedings
are also included. As a rule, organizations and States
authorized to participate in the proceedings may submit
written statements, followed, if the Court considers
it necessary, by written comments on these statements.
These written statements are generally made available to
the public at the beginning of the oral proceedings, if the
Court considers that such proceedings should take place.
Contrary to judgments, and except in rare cases where it
 is stipulated beforehand that they shall have binding
effect (for example, as in the Convention on the Privileges
 and Immunities of the United Nations, in the Convention on
 the Privileges and Immunities of the specialized agencies
of the United Nations, and the Headquarters Agreement
 between the United Nations and the United States of America),
 the Court's advisory opinions have no binding effect.
The requesting organ, agency or organization remains free
 to decide, by any means open to it, what effect to give to these opinions.
Although without binding effect, the advisory opinions of the
Court nevertheless carry great legal weight and moral authority.
They are often an instrument of preventive diplomacy and have peace-keeping virtues.
Advisory opinions also, in their way, contribute to the elucidation
and development of international law and thereby to the strengthening
of peaceful relations between States.