It has gotten more scary, especially in the last year or so, with Trump violating norms of behavior and political speech just about every day. Once a nation starts following an authoritarian figure like Trump and puts him in power, it becomes very difficult to get back to democracy. Authoritarian regimes typically don't tolerate dissent, especially armed dissent.
Even if Trump doesn't win, he has "broken the mold" of precedent that governs how candidates for president behave and speak. He's made it easier for the next authoritarian figure that comes along.
Taking up arms against the government is illegal, period. In the U.S., the so-called
Whiskey Rebellion occurred and was put down relatively peacefully in 1794, just 7 years after adoption of the US Constitution. The American Civil War was started in 1861 by rebellious Southerners who forcibly
occupied a federal military facility in South Carolina. On the other hand, the U.S. was of course itself formed as the result of an armed rebellion against Britain. This was regarded as an act of throwing off oppression, justified by natural law in which human rights take precedence over the state. So, if people seek to throw off an oppressive government, they may have justification in natural law philosophy. If they take that route, for their sake, they'd better win.