The founding of the US is absolutely a remarkable achievement. A group of colonies successfully broke from global imperial power to successfully establish a society heavily influenced by the best enlightenment thinking and classical civil philosophy. It's really something. Looking at some populist reactionary movements that happened in the early 19th century, one wonders if the outcome could have been as good as the US constitution even 30 years later.

That said:

* it existed in a historic and cultural context of states that had already made significant movements in that direction -- it was a big leap, but it wasn't simple 0-1. More like a 0.4 with a lot of the relevant ideals and institutions (elections, representation, courts, legislative bodies, executive authority, rule of law , etc) fairly well developed and demonstrated in various ways pulled together into a coherent 0.75 and woven in with enlightenment ideals as expressed in documents like the declaration of independence.

* There is at least a partial linear dependence between civil rights and democracy. The franchise relationship is where it's strongest. Democracy is effective, principled, & honored ballot access. Without any effective franchise what you have instead is an opinion poll. And mere fractional access to the franchise walks elections & representation down from "1" -- it is literally the coefficient you have to multiple a "1" democracy by in order to arrive at its effective democratic nature.

That's just the start, though. It's a bit like that old Churchill/Shaw/Twain/whoever story where Clever Guy™ is having a conversation with a woman:

    “Would you sleep with a stranger if he paid you £1,000,000?” 

    “Yes.” 

    “And if he paid you £5?”

    “£5? What do you think I am?”

    “We’ve already established that, now we're just haggling over the price.”

Ha-ha! A country without a universal franchise has already established that some people don't get a democratic say, it's just haggling over who those people are. And that means it can haggle over whether you get to be one of those people. And even eventually over whether anyone gets to be one of those people, over whether it is democratic at all.

This generalizes to other rights. In order to have them guaranteed to anyone, they must be guaranteed to everyone. It's why constitutional guarantees tend to be features of constitutional representative democracies since the enlightenment, imperfect leap though the US is.

The big question is if the US (among others) can finish climbing the ladder when the political headwinds seem to be against "guaranteed to everyone."