You have three branches, for checks and balances, and gave one of them command of the entire US military. It seems not so much a stretch of imagination that that one may go rogue one day.
The thing is, no political system is foolproof and free of issues. But the US and the UK are about the only major countries in the world that didn't experience a forced reboot of some sorts - wars, revolutions, secessions, whatever - that brought an update of the constitution and legal system with it. Everyone else, however, did and learned from the issues that they and other countries had experienced in the meantime.
By now, the US is running on the same system for over 238 years. Yes, there have been some updates and amendments, but the fundamental assumptions are still the same stuff from centuries past, when virtually instant, global communication and transport of goods and people wasn't even thinkable.
The US didn't have a military and resisted having a standing army until WWI.
Maybe they figured if things get too bad, officers of good conscience would stem the madness and have some political/legal cover from the other 1-2 branches? Eg. If a president tried to give orders to the military after being impeached and removed, it's doubtful they'd be followed.
The problem then is compounded by the fact the president picks the secdef, and is more or less able to fire anyone showing an ounce of 'disloyalty', as we've seen happen in recent weeks. Twice if memory serves me right.
So all but the very dumbest would curate their military leaders before attempting boldness.
It took us 48 years to get rid of our dictatorship, and in theory there were multiple occasions where the militar could have joined to take it down, it was only when the colonial wars got bad enough, that there was enough people in the movement to have made it possible.
And to make a point out of it, the laws imposed by the Allied did nothing to prevent what happened in East Germany and Stasi deeds after that law came to be.
Trying to work out which country you're referring to - Spain? Portugal? East Germany?
> laws imposed by the Allied did nothing to prevent what happened in East Germany and Stasi deeds after that law came to be
Well, yes, I should probably have clarified West Germany, a different country from East Germany, due to the Soviet control at the end of WW2. I suppose the point is that no legal order withstands overwhelming force in the end.
I belong to the first generation growing up as a child after the dictorship ended, thus like many people around the world in similar circustances, I do happen to have a close relation to what it means, and stand by the revolution cries "25 April forever, fascism never again", that unfortunely many in voting age have no clue what it actually means in practice, hence we have our own issues coming to our shores with Chega party.
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.—That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed,—That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.
The founding fathers were big fans of the philosophy of John Locke and his social contract: https://en.wikipedia.org/wiki/John_Locke https://en.wikipedia.org/wiki/Social_contract
Locke also advocated governmental separation of powers and believed that revolution is not only a right but an obligation in some circumstances. These ideas would come to have profound influence on the Declaration of Independence and the Constitution of the United States.
Our founding father's were very very liberal and strongly believed in a consent based government which implies the idea of revoking consent. When a government starts acting in ways you cannot consent to, like invading Canada or Greenland, robbing people of due process, preventing trade, and refusing to be bound by law, they had a very clear answer. You can find many Jeffersonian quotes about this very idea that many young Americans hear from their fathers and grandfathers, sadly many of those once young Americans have been corrupted by fox news.
The writer of the declaration of independence and third president of the united states chose "Rebellion unto tyranny is obedience to god," as a motto on his personal seal: https://www.monticello.org/research-education/thomas-jeffers...
People asked, at the time, if that applied to women or black people, and after considerable argument concluded that the answer was "no". From that stems a lot of America's problems.
The American Revoltion actually sparked a first round of antislavery laws and court cases, which eliminated slavery in the northern states within a generation. Even in parts of the South, there was increasing questioning of slavery. The US banned the international slave trade. Virginia made it legal (for the first time) to free slaves, and there was a small wave of manumissions. People like Thomas Jefferson admitted that there was something wrong with slavery, even if they were so financially dependent on it that they didn't free their own slaves. Jefferson even drafted a new constitution for Virginia that would have freed anyone born after 1800, but shelved it when he decided it wouldn't have enough support to pass.
Vehement proslavery ideology really developed a few decades after the revoltion.
It was badly engineered.
And it was overly confident on trust over the course of events and human nature - while you are obliged to do the opposite.