He never wanted to become a Nazi - he practically invented the thing (he had help though).

How he became a Nazi goes approx. like this:

- Daddy didn't give attention, Mommy didn't care -> he became an outsider and megalomaniac.

- Went into the trenches in WW I, got traumatized -> became a bitter megalomaniac

- Since Daddy never gave attention, and no one wanted to buy his painings, he even got rejectes at art school -> he then sublimated that in political megalomania and revolted (in the street, together with other dirsturbed characters in Munich).

- Got imprisoned (in Landsberg) due to failure of said revolt -> proves him a lousy amateur with megalomania

- But used the time in the bin to plot, regroup, build a strategy (became a semi-pro) and wrote it down ("Mein Kampf"), got released eventually. Now he was a semi-professional, bitter megalomaniac with a plan, seeking revenge (and then finally getting attention from Daddy)

- Met dangerously clever, but totally twisted people with secret society background (Thule Society).

- Got training from them (acting, rethorics, strategy, tactics, ...), education, contacts, and funding -> makes him a professional, well trained, twisted, bitter megalomaniac demagogue.

- started professional politics, based on the old scapegoating-game and adressing, at first, other disapointed, traumatized lads. (antisemitism was quite popular then, all over Europe and some other parts of the world. before the mid 20ies he reportedly never stated anything comparable to his later gross anti-semitism, even had a Jewish roomate in Vienna)

Das Führerle (with a couple of other guys, with support of the Thule people etc.) literally invented 'Nazi' (Nationalsozialismus, 'national socialism'). Created his niche in the poitical market. Had brilliant spin-doctors.

Then some clever moves (lying to the right people, e.g Hindenburg), some evil moves (intimidation, intrigue, murder), and a society frustrated by the inertness of the poitical system at that time and by poverty, inflation etc.

Voila, les Nazis take over. Got legally elected. Then stuck to the original plan and hyped their way to totalitarism within months (again: murder, fud, bribery, ...).

After all we're quite lucky that he never got cured from his original trauma, so he got selfdestructive (typical megalomaniac). Otherwise, maybe we would all be listening to marschmusik and be sauerkraut-vegetarians (like Adolf) - except that most of us would not be here! (Google for 'euthanasia' and -in theory!- apply the criteria of 33'/'45 to people you know, and to neo-Nazis, boy if they knew... that most of them never would've left the hospital after their birth. creepy eh?)