Europe has been under stresses that are not really comparable with what the US underwent in 2 centuries. The only really existential crisis was the civil war, whereas most European countries have been invaded a couple of times, and almost all of them had battles on their soil.

It is true that some compromises were needed because of its federalist character. In this it is much closer to Germany than to France.

> It's almost like a bunch of highly educated and intelligent individuals spent several years studying the failure modes of previous republics and then designing a system that would be robust against those failure modes.

I am not really disagreeing with you here, but what makes you think that this was not the case in other countries? Were there no highly educated and intelligent people in Europe for 2 centuries?

There was a lot of cross-pollination between France and the US at the time of the revolution, several people were involved in both. The American constitution is built on enlightenment values that were quite widely shared and Europe was not short in political thinkers either. A lot of them also benefitted from the American example.

What ended most of the French republics were coups d’états and wars. As in “the enemy is a 2 hours drive away from the capital”, not “let’s bomb another country on the other side of the world”. It’s not because of its immutable constitution that these things did not happen in the US.

In short, I think smugness is unwarranted, and the US is not immune to coups d’états, even if its geography precludes almost any wartime occupation. Also, philosophers in the 18th century were not super-human. Their work is not perfect. The lack of evolution leads to fossilisation and a shift of power towards the Supreme Court. This is a serious threat to the separation of powers, and should be taken seriously.

There are other failure modes that have been made clear in the last 2 centuries, Americans would be wise not to dismiss them and learn from others, as other learnt from them.