The students can take the following topics for debate and finally conclude, UN is successful as it has stopped the nations from bringing another war. Small to big clashes were/are handled by UN efficiently.

Argument for: 

The topics of discussion for debate are:

1. Solving International conflicts: Since 1945, UN peacekeepers have undertaken over 60 field missions and negotiated 172 peaceful settlements that ended Regional conflicts. 

2. Liberation from Colonial rule: Eighty nations and more than 750 million people have been freed from colonialism. 

3. Human Rights: Custodian for the protection of human rights, discrimination against women, Children’s rights, torture, missing persons etc. in many countries. 

4. Enhancing Human life: Specialised agencies of the UN engaged in enhancing all aspects of human life, including education, health, poverty reduction, climate change. 

5. Treaties: More than 560 multilateral treaties on human rights, refugees, disarmament.

Argument against:

Non-proliferation Treaty (NPT): Signed by 190 nations, all live superpowers owned nuclear weapons. Later, several countries North Korea, Israel, Pakistan, India developed nuclear weapons.

Veto Power: Veto power has limited its effectiveness at critical times.

War Criminals: The International criminal court has prosecuted several war criminals. But it has been criticised for prosecuting only African leaders. But Western powers too have committed war crimes.

Israel Attack: Israel attacked homes schools, U.N. shelters in Gaza killing 2,200 Palestinians. The U.N. Security Council has failed any action against Israel.

Conclusion: U.N. is imperfect but it is also indispensable. It is successful as, it is avoiding any other war.