Here is the Convention on the Prevention and Punishment of the Crime of Genocide (PDF).

And here are some important articles everyone should read:

Article I
The Contracting Parties confirm that genocide, whether committed in time of peace or in time of war, is a crime under international law which THEY UNDERTAKE TO PREVENT AND PUNISH.

Article III
The following acts shall be punishable:
(e) COMPLICITY in genocide.

So far, there are less than 10 countries actively taking measures against Israel (Bolivia, Venezuela, North Korea, Nicaragua, Colombia, Cuba, etc.)

ALL the other countries are ACCOMPLICES by default, and guilty of disrespecting this document they ratified.

Watch also this clip of the The Electronic Intifada Podcast analysing the prove of genocide intent: