“Do not compare yourself to others. If you do so, you are insulting yourself.” ― Adolf Hitler
Both politicians claimed to have their country's best interests at heart. Trump has an entire team spinning his every word to the public and manipulating his outward-facing persona. Both Hitler and Trump use the same weapon; they exploit fear in a pernicious & highly dangerous manner. History proves we should never assume that he'll lose.
Noam Chomsky's comparison of Trump to Hitler is fair. First of all, it is his opinion and he is entitled to that here in America. Second, it is easy to support this comparison at least politically. Trump made hateful statements against entire groups of peoples as Hitler acted out in Germany. They both utilized people's discontent to further their agendas.
Donald Trump has been a moderate liberal for his entire public life. He, as many politicians do, catered to far right wing voters to gain their support. He has already backtracked on many of the more controversial comments he made during the campaign. Extreme lefitist like Noam Chomsky are just upset that they have lost some power.
No one ever compared Donald Trump to Hitler before he decided to run for President. People got scared, and then decided to start calling him names. Calling someone Hitler is just dreaming up the ultimate insult. Trump had a way or rallying the low-information Republican voter. That is not fascism, it is good marketing.