Would the Nazis have achieved power without Hitler's charismatic manner?
It is highly doubtful if the National Socialists would have been successful if not for Hitler's charismatic speaking and organizational ability.
The National Socialist German Workers Party ("Nazi" was a pejorative term) was one of a number of such organizations active in Germany after the World War. The party had been in existence for several years before Hitler joined; in fact he was sent as a spy by the army to a party meeting to report on its activities. He had remained on active duty in the army after the end of World War I because he had no where to go. His orders were to attend a meeting, sit quietly at the back of the room, and take note of any subversive activity. Instead, Hitler became very caught up in the discussions at the meetings, made a number of intemperate speeches, and caught the attention of party officials who actively recruited him to join the party. He only agreed to do so if he were allowed to organize the party in his own way. Through his mesmerizing speeches and organizational skills the party over time gained a majority in the German Reichstag and thus took over the government.