Existing International Authorities and Principles 

Prior to World War II, the world lacked an effective international governing authority, existing instead under customary law and a collection of sparse treaties. Because of this, what are today considered inalienable human rights were left unprotected.

---

The Rule of Force: Victor's Justice

Victor’s Justice is the concept of a conquering nation exacting its own definition of "justice" on its enemy. In other words, using Rule of Force rather than following written law.

For example, the Versailles Treaty, signed after World War I, outlined the peace agreements between the Allies and Germany.  David Lloyd George, of Britain, promised to "make Germany pay" through post war negotiations.

---

The Existing Treaties

                           "Considered as embodying rules of customary international 
                                               law...binding on states which are not formally parties to them." - ICRC.org

Hague Conventions of 1899 and 1907  outlined the customary laws of war in regards to sea, air and land. 

1907 Convention

Geneva Convention of 1929 was in response to World War I and concerned the treatment of prisoners of war and the wounded.

Geneva Convention of 1929

While there were existing agreements pertaining to the atrocities of World War II, they were not legally sound enough to be effectively enforced. 

---

Pact to Outlaw War

"[The] renunciation of war as an instrument of national policy."
-Kellogg-Briand Pact of 1928
(also known as the General Treaty for Renunciation of War as an Instrument of National Policy)

Senate Approval Headline