I think people should realize that, in a democracy, it is virtually impossible to put these safeguards in place if people at large don't want them.
The reason Trump is able to get away with so much right now is because Congress is letting him. They could easily constrain his tariff powers, or his warmongering powers (they actually were close to doing that WRT Venezuela before some Republican Senators caved like a bunch of wet blankets), but they don't, because this is what people voted for. Trump is so much more powerful in his second term because at this point everyone knew he was a convicted felon, they knew he fomented the attack on the Capitol, and still a majority of voters voted for him.
Safeguards only work of someone is willing to enforce them.
It may not be possible to do perfectly, but here are many things that can be done to make it harder.
E.g.:
- no direct elections of a president with such broad powers.
- Separating the head of state and head of government, and split their powers.
- Proportional representation to reduce the chance of the largest party obtaining so much power alone.
- Not letting the president appoint supreme court justices.
- No presidential pardons; basically removing the chance of getting out of protections against legal sanctions after leaving office, and removing one of the strongest means of protecting loyalists.
The US isn't uniquely vulnerable, but it is a whole lot more vulnerable than governments in countries where the head of government is easier to replace and have fewer powers vested in their own personal mandate.
A direct election of a single powerful leader is also fundamentally creating a less democratic system - it reduces the influence of a huge minority of the electorate far below what their numbers justify.
The reason Trump is able to get away with so much right now is because Congress is letting him. They could easily constrain his tariff powers, or his warmongering powers (they actually were close to doing that WRT Venezuela before some Republican Senators caved like a bunch of wet blankets), but they don't, because this is what people voted for. Trump is so much more powerful in his second term because at this point everyone knew he was a convicted felon, they knew he fomented the attack on the Capitol, and still a majority of voters voted for him.
Safeguards only work of someone is willing to enforce them.