You are again comparing the flawed US "democratic" system to a real democracy. Trump should not be able to gain those tools because a functioning democracy protects the rule of law and holds justice to be above all other concepts. In the US, the legal system is a sham and the levers of power are easily taken for abuse (not to mention corporate capture of the two political parties which control all political life). So while Trump should not be able to capture those tools, it is only possible because the US does not have a real functioning democracy. In places like France, the state ensures that it is not possible to easily take complete power as Trump has in the US.
In short, no, Trump should not be able to take these tools. But in actual democracies they have checks to ensure that this is not possible while in the US no such checks exist.