Genocide, How to stop them...? Options

[FoOd]

Okay, I hope this is in the right forum, but I have been wondering,
How can a genocide be stopped?
What is a genocide? Basically for a brief definition, it is the mass murder of a certain race by another certain race.
Take the Holocaust for example. By far, I think in my opinion, was the worst genocide in the world's history, but lets not stray from the topic I was originally planning.

So how can a genocide be stopped?
Killing the leader?
Nuke them out?
Peace treaties?
Full out war?

Ideas would be nice. This was a way to see what some people might think.

In my opinion, there is no certain way to end a genocide. There might be a way that will work for one genocide, but there is no rigid choice that would work for all genocides.

So, how can all genocides be stopped if more were to ever occur?

[*mona lisa*]

Now that I read a few of the posts, the Haolocaust is a little overrated.

And one reason why genocide starts because the leaders want to get rid of dissents and those they think or claim are inferior to them. It's really hard to stop one also. I mean if someone was on a killing rampage, then...it would be difficult. I think it might be easier than before because of technology. It depends on what form of homicide you want to commit (I mean as in getting rid of the leader so the whole thing would come to a halt or slow down). If you want to kill the leader, then you can do it in ways that did not exist when Stalin or Hitler were alive.