The very first requirement is do an act "with intent to destroy". The intent is the distruction of one on the listed groups - in whole or in part. A cossack in Poland in 1813 with the intent to rob and steal from the locals, but without the intent to destroy one of the listed group would NOT fit the definition. The French army in Spain with the intent to terorize the local population into forgoing support of the local resistance fighters would NOT fit the definition.

It is necessary to satisfy the first part before the remaining parts come into play.

Steve