The post in question regarded the Third Amendment, and so to address the first piece of this post’s title, The Bill of Rights (amendments 1-10) is considered separate for some practical purposes, but really is just the first set of amendments to the Constitution. It’s like buying a new car and immediately sending it in to the shop to be pimped out, and thusly America was born.
But the burning question is this thing about “pre-existing rights” and where they come from.
Part of the evidence is grammatical with regard to the US Constitution, the Second Amendment gives us one of the best windows through which to look at this idea:
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
Emphasis mine. It’s not “the people shall have the right”, but “the right of the people”, this gives us an indication that there is an underlying right here, it wasn’t created, it was named, described, studied, observed, perhaps, but just like Darwins Finches, they are not human creations. This, of course, makes perfect sense. Governments are imaginary in the sense that they exist only in the mind, you can’t hold a government, or poke it*, and be thankful for that, because governments poke back.
The Bill of Rights guarantees certain natural rights, it does create some, the right to legal counsel for example, but those are more the exception than the rule. That makes a lot of sense because with no governments there would be no need for legal counsel. I would even go so far as to say that, we don’t actually have a right to counsel, but rather that the government has a constraint placed upon it**. To top it all off the 9th Amendment says:
The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.
In case it wasn’t clear enough before not only does the Bill of Rights enumerate, list, rights considered to predate the Constitution, it only lists some, and it specifically references other rights that clearly must also exist outside of the framework of the Constitution since they are not listed within the text.
So where do these rights come from? Well, God. However it isn’t really a religious notion, specifically we are talking about the idea that these rights come from something that preceded governments and, more importantly, supersedes them. God is a fine word for the concept, but one who isn’t religious might say that some rights are part of the very fabric of humanity, or stem from nature itself, not from institutions created by humans.
We have the right to free speech, religion, assembly, self defense*** and so on. We have these rights by virtue of our existence, not because we live in this country or that.
We can argue over whether a particular right is “God-given” or not, but the concept of natural rights is central, not only to the US Government, but also to those of many other countries and also on the international scale when you consider things such as The Universal Declaration of Human Rights.
Perhaps what is most significant about the concept is that even if we were to repeal the Bill of Rights, we would retain the rights of free speech and such. For example, if you read or listen to the oral arguments and the decisions in D.C. v. Heller and McDonald v. Chicago you’ll find that even without the 2nd Amendment that right would be retained in some form.
In the end it’s important to recognize that what are considered to be natural rights can change with time, but the concept does not, and that is vitally important to overall liberty, otherwise we would have no rights, but rather only privileges given on the whims and impulses of the government in question. What the government giveth, the government can taketh away.
*That isn’t to say that the government shouldn’t be small enough to drown in a bathtub.
**It amounts to the same thing. It’s just a way of thinking about it that resolves some of the problems brought to bear if you start proclaiming the existence of positive rights. One doesn’t have a right to a lawyer, the state is required to provide one if it wants to take your life or liberty.
***The Second Amendment recognizes the right of self defense and specifically restricts the extent to which the government may infringe upon it, guaranteeing the right to use arms, for example.