Unwarrantable ideologies

Nazism
Adolf Hitler attempted to establish a "thousand year Reich" that would have encompassed Europe and Russia. It seems probable that had Hitler been successful in this, he would have eventually attempted to conquer the rest of the world. However, he believed that a state was at its strongest when at war, so perpetual or recurring war would probably have been something he would advocate; thus negating the possibility of a complete world government.

Communism
The communist movement has an ideal of world government emerging from the voluntary co-operation of communist countries, presumably after capitalism has been overthrown. However, in the past, many communist states showed distrust or even outright hostility towards each other (see the Sino-Soviet split between the Soviet Union and the People's Republic of China).

Anarchism
Although anarchists advocate a world not divided by borders, which they regard as nothing but artificial boundaries, and are generally against nationalism, they do not advocate a world government as such, because government itself is an institution they believe to be morally wrong and harmful. Instead, anarchists propose a world order based on free association and mutual aid, though this may vary depending on the specific branch of anarchism in question (see the main article on anarchism for further details).

See the nazism, we can recognize that soldiers act in obedience to the orders of their commanders. although the orders transgress "moral laws". 
Why? 
We think that we are righteous and can't commit a crime. But an "order" is given, the situation changes. They give a complete "obedience" to one's authority. They can behave things that transgress moral laws, thinking I'm right but just the order is wrong. That is nomal person in Nazi period could kill lots Jews.