What is the danger of lenin's idea of party leadership? 2. making inferences why did the germans allow lenin and his associates to return to russia? 3. recognizing facts and details what obstacles did lenin have to overcome to achieve his revolution?

The danger in it lies in the fact that Lenin believed that the party leadership must be obeyed without question since the party was the will of the people so questioning its leadership would be questioning the entire population of the country. This is dangerous because the leadership might make harmful decisions but the people would not be allowed to question it. 

Germany and Russia were in a war and the Russians were pressuring the Germans heavily from the east. The Germans believed that if they helped Lenin help back he would disrupt the government which would create problems in the Russian war effort, which more or less did happen since the Soviets left the war after the Bolshevik revolution

For starters, he had  to be smuggled back into Russia since he was a wanted fugitive and was in exile. Another was that he had to organize an entire coup and a revolution since it would be impossible for him and his supporters to get power in the country in a legal way since communism was more or less banned and people would be arrested.