Trump won't succeed unless we let him.
The U.S. in 2017 is not the Weimar Republic of 1933. Trump isn't Hitler.
For example, Hitler had the benefit of the unexpected in 1933. No historical figure in government ever got away with what he did, so the response was inadequate. Also, German society was primed to be obedient to authority. Everything from a leader and followers in the Church, school/universities, government, the social clubs, and of course, the home. When Hitler gave an order, there was much societal pressure to bend to his will. And if you were independent enough to challenge his way of doing things, there were the Brownshirts to get you in line or in a camp. And the first thing Hitler and his thugs did was to take over the courts to ensure there was just one kind of Justice: Hitler's.
We aren't there. We know to some extent what to expect. We are too independent to go along like lemmings for four (god forbid, eight) years of Trump. We have a Constitution and we have elections. We didn't let Shrub shut down democracy after 9/11 and there's no guarantee that Trump would succeed if he tried some maneuver like that in a true or staged national emergency.
We need to organize in local, regional, state, and national groups and stay active. OTOH complacency will be our downfall. We have to pay our dues as citizens and we're going to be tested no doubt.