A very interesting topic, which can be cleared up by visiting
the home page of the United Nations, and a search through the
United Nations Charter will reveal some interesting
information.
The United Nations consists of three main bodies:
The General Assembly, the Security Council, and the
Secretariat
The General Assembly - of which all nations of the world may wish
to join as ordinary members, to benefit from the resources of the
various programs developed by the UN.
The Security Council - form with Five Permanent Members - (China,
France, Russia, UK, and USA) - and Ten Non-Permanent Members from
the General Assembly who will sit for a two year term.
The five permanent members carry the right to veto any vote.
All members at the General Assembly are independent nations, and
each country's sovereignty are respected by all members, and are
willing to submit themselves to the rulings of the United
Nations.
The General Assembly will select from their ranks, ten members who
will be vote carrying members to represent the General Assembly at
the table of the Security Council, and will sit with the other five
Permanent Members to oversee Security Issues affecting the entire
World.
The role seems to be quite well defined between the General
Assembly and the Security Council.
The General Council will concern itself with the elevation of the
living standards of the world population so as to maintain World
Peace, by promoting progress in development through economic,
social, cultural, health, education activities.
The Security Council has been given the role to oversee and
deliberate any necessary response to maintain security in the
World, and operates without recess through the year.
The Secretariat, in which the UN Secretary General has his office,
will see to the smooth functioning of the United Nations, advising
the General Assembly of the proceeding at the Security Council, and
to update the member states when the General Assembly is in
recess.
There is no question of the General Assembly trying to overturn any
decisions made at the Security Council, as ten of the fifteen
members at the Security Council are representing the members of the
General Assembly.
To change this Charter that affect the current United Nations, it
will require the General Assembly to pass a motion with two-thirds
majority, and the Secuity Council to approve the same with a vote
of nine out of fifteen.
From the following website, see the following
concerning:
http://www.un.org/aboutun/charter/
General Assembly - its role and authority
Chapters: IV, IX, X
Security Council - its role and authority
Chapters: V, VI, VII, VIII, XII
The Secretariat - its role and authority
Chapters: XV
Particular relevance to Singapore in the Water Dispute with
Malaysia is Chapter XVI, Articles 102 and 103.