Ancient Egypt wasn't all that isolated. They had threats from the west, south, and north.

> Like, I believe that China did have periods of peace that would have been long enough to develop liberal democracies. China was the strongest country in their region,

China was not one country until 220 BCE, and afterwards, they had to adopt an imperialist expansionist policy to shore up their borders. They had a long period of political stability, but they still had to defend themselves from threats without. Democracy only happens after all these are removed so the population can build up the political will to challenge the power structures.

It has a flow to it, the building up of democracy. Power flows outward from the ruler to an aristocracy, which eventually engages in trade, building up the merchant class. In order for citizens to want to participate in a democracy, they need to be economically well-off, this means something like a middle class.

Countries go through these phases all the time, but only in a really geographically isolated place can they actually build to the point where there's a real democracy.

> sure they had borders to watch but they were just as protected as France or Germany during their conversions to democracy or republics.

France's democracy disappeared quickly with Napoleon and to me is an example of why isolation is absolutely essential to safeguard freedom. French Republican armies were nigh-invulnerable, and this whetted their appetite for empire. Napoleon gave them what they wanted. Again here, the world at large ruined their ability to self-govern.

Germany's revolution was not a democratic one, but a socialist one. The socialism of the day was totalitarianism in democratic clothes, this to some extent remains true. Populists turn autocratic very quickly after getting elected. Germans of the era were every bit as militaristic as the French were after the Revolution.

> being cast off from europe (their legacy bureaucracies didn't suppress innovation), being free-market inclined, having a group identity ("American") that all migrants can share, practicing freedom of religion and inheriting the british common law framework.

These are all outgrowths of geographic isolation.

The reason Europe left them alone was because it they were too busy dealing with each other, America was too far away for it to ever be more than a side-show.

A free market flourishes in the kind of democratic environment that comes from isolation. Remember the Dutch and the British were the commercial masters of the colonial age, both nations were extremely well-isolated.

The group identity aspect Americans took straight from the British, it's a very British idea.

English common law is, again, one of those social innovations that can only come from a long period of time where there is no credible external threat sapping public will to uphold legal freedoms against aristocratic depredations.

You should read the very excellent Inventing Freedom, it elaborates on how British legal and commercial innovations came to be.

http://www.amazon.com/Inventing-Freedom-English-Speaking-Peo...

> W/r/t to legal systems collapsing, they're protected by guns and myths.

This is true enough in many parts of the world, but a careful reading of the history of English Common Law reveals a fascinatingly iterative legal process that formed a bulwark against monarchal oppression for hundreds of years.

For a good introduction, check out this book:

http://www.amazon.com/Inventing-Freedom-English-Speaking-Peo...