You're looking at this through a profoundly anachronistic lens.
The Founding Fathers were informed by the Western Canon, namely the historical examples of Greece and Rome. Athens was the poster boy for the rise and fall of nations. The steps were roughly:
-Aristocracy
-Oligarchy
-Democracy
-Tyranny
In this telling, the tyrant is the self-proclaimed champion of the people, who directs the emotions of the people for self-serving reasons. This may, at first glance, seem to describe Trump, but in antiquity this was linked to class envy, which in modern times has been the near-exclusive domain of the Democratic Party. Parties are not individuals, of course, which makes this connection harder to spot, but one could view the Democratic Party as the well-organized pursuit of tyranny in updated form: the one party state.
What separates aristocracy from tyranny is checks and balances. The aristocrats, where distinct from oligarchs, were subjected to the just laws of the land, because no one man could hope to overturn them and because the bulk of the aristocracy had no desire to overturn them. In contrast these no longer exist by the time the tyrant sweeps into power. After all, laws (e.g. laws protecting property rights) may potentially frustrate the sacrosanct majoritarian will and so will be inherently suspect in the late democracy. "What the people want" will take the place of laws, and where the tyrant/tyrannical party succeeds in channeling the concept of "what the people want" into his own person/its own apparatus, then he/it becomes the ultimate authority.
Again, this is the party to a T.