Hi. I'm a U.S. citizen and a JHS/HS civics teacher. I've enjoyed this discussion by (mostly? All?) non-citizens that show what I've told many of my fellow American citizens for years: you look like buffoons not knowing as much about some other country's political system as everyone else knows about ours. I wouldn't be surprised if some of you are dual citizens, or like me, someone with multiple residencies, which puts us in a different position than most of our fellow USians.
The Constitution is very hard to change, but due to Judicial Review, it's not hard "to reinterpret." It happens all the time, which is why there is always a fight to stack the court with ideologues. However, this fails about half the time, because the U.S. judiciary is an independent judiciary. Much is made of the fact that they are, at first, political appointees (nominated by POTUS, confirmed by Senate majority), but what people often miss is the records of justices after they join the judiciary. Justices serve for a term of "good behavior," or, you know, forever. They cannot have salary reduced, they can only be impeached under extreme circumstances, they cannot really be punished. Presidents often find, as Bush did with Roberts, that once a justice realises that independence and power, trying to control their judicial appointees is a crapshoot for any sitting President. That's a feature, not a flaw.
If massive change comes to the U.S. system, it will not be because Trump and company successfully use the levers of government to create intra-constitutional changes leading to what is known as an illiberal democracy (where people really did vote the dictator in, and the dictator uses democratic processes to stifle civil liberties, usually due to fear of the other, either internal strife or external enemies), but rather by out-right extra-constitutional methods supported by enough of the populous to keep various checks and balances of the other co-equal branches of government from doing their jobs.
tl;dr Trump becomes a fascist dictator, or more likely a figurehead to the likes of Bannon and Miller, not by changing the Constitution, but by setting it on fire while no one cares.