Answer: He realised the best way to win true power was by constitutional means.
Explanation: Adolf Hitler was found guilty of treason and sentenced to five years in Landsberg Prison and on 20 December 1924, having served only nine months of his 5year sentence, Hitler was released. By this time, his political position and connection was stronger than it had ever been.
During his incarceration, he made a discovery and decided that the success of the Nazis could not be guaranteed by a violent overthrow of the Weimar Republic which was in power at the time, but by gaining power through constitutional means.
He also decided that once he legally gained power, he could transform Germany into a nation that aligned with his doctrine and move the nation forward in any way he chose as well as carry out all his plans.