Genocide's can be prevented

To prevent a genocide the biggest factor is recognition.  There are eight stages that appear in all genocides and if these steps can be recognized as the steps they are, something can be done to prevent them from continuing.

1. Classification is distinguished categories based on ethnicity, race, religion, or nationality.
2. Symbolization is the names or other symbols given to the classifications. 
3. Dehumanization is one group to “deny the humanity of the other” and  associate them with animals, insects and diseases. 
4. Organization is the plan for the killings..
5. Polarization is when two groups are driven further apart by polarizing propaganda and laws prohibiting social interaction between the groups.
6. Preparation is when victims are identified and segregated.  Often they are relocated to ghettos, camps, or famine-struck regions where they are destined to starve. 
7. Extermination, called extermination because the killers do not view their victims as even human, this stage is the actual mass killings.
8. Denial: Denial always follows genocide as the final stage.  They blame it on the victims, hide all evidence, report false information, intimidate witnesses, and deny investigation. 

At any of these steps the genocide can be stopped, if enough people recognize what is going on and take steps to prevent it from continuing to it's final stages.  
Since the Holocaust which is notably the most recognized genocide, genocides still happen and continue to happen today.  Read about theses genocides here where Nate Fuller addresses the 9/11 attacks, here where Grant Solis refers to the genocide in Darfur, and here where Ayden Carver addresses Japan and Korea.