They mark limits on government power. If you or I have some right or other, it means government is excluded. If we own some property by right, its agents may enter only by permission – or else by force, violating the right. If we have the right to remain silent, its agents may not rightly oblige us to speak.
Government really, really doesn't like limits, and in fact if government exists, it allows none in its domain; it may pretend there are a few, but that's only to keep folk from becoming alarmed. That's the nature of government: it governs. Individual rights are incompatible with government. The primary (sole?) business of government is to prevent individual rights being enjoyed in practice. If you want rights in practice, you have to terminate government.
So when a distinguished politician once wrote “All men are endowed by their Creator with certain unalienable Rights”, he was either hopelessly naïve (unlikely) or deeply hypocritical – as suggested by the phrase which followed, about government existing to “secure” our rights. Correct: Jefferson actually said that history's primary rights-violator is supposed to secure rights. It is astonishing that anyone can repeat those words and not gag on them. Jefferson was smart and well-read; it's not credible to me that he didn't know what nonsense he wrote.
Similarly, when anyone says that “rights” don't exist, or that individuals don't have any, such as the right to privacy, which the Feds are currently violating so massively, or (worse yet, though surprisingly common) that we have only such rights as the government is graciously pleased to grant, either he doesn't know which way is up or else he's a government disinformation agent. One or the other, take your pick. Prominent pols would not say such things openly, for doing so might lose votes, so it's understandable that they get others to convey the news, preferably a little at a time like water dripping on a stone. Hence, government schools.
However, having used the word for four paragraphs, I ought to define it – for it is admittedly a slightly difficult subject. Let's dispose first of a few things it doesn't mean.
The word “right” is being used here as a noun, not an adjective. “I am right” about this and all my adversaries are wrong – yes – but that's not a noun. Nor do I refer to being “right” morally, while others are sunk in iniquity--even if they were. So those uses are not in consideration.
The noun “right” can itself have two shades of meaning. By contract, if I hire a car, I may have the “right” to drive it from sea to shining sea before I hand it back with a large check, but that too is not what is meant. Or if I'm a strict parent and give my teenager the “right” to stay out until 10 pm, that isn't it either. Those kinds of rights are transitory, not permanent or ingrained or “inalienable.” Government may delight in allowing its subjects to have that kind of right from time to time – the “right to vote”, for example, because voting is harmless to them; it makes no difference. It's good PR, and helps keep the sheeple content . . . for a while.
No, the right under discussion is something not subject to being granted and/or taken away; it is in-built, ingrained, integral to each human being as part of his or her nature. One neat way to define it is as “an action for which no permission is required.” It is a word we use to express absolute self ownership. We each have the right to own, operate and control our own lives because we are members of the human race; man is a self-owning, reasoning animal. It's what we are. It's a form of short-hand; instead of saying “since I am a self-owning human being and have a mouth, I can speak or not speak without limits”, we say we have the “right to free speech.” It means the same, it's just quicker. It's a handy word.
Perhaps that makes it a bit clearer why individual rights are so repugnant to rulers. If the ruled have rights, the ruler's rights are reduced. Indeed, when we get to think about rights, we might ask by what right rulers rule; and that's a very tough question for them to answer. For a very long time, they asserted that God had given them that right. This was okay when nearly everyone believed that a supreme (but invisible, inaudible and untouchable) being existed, but it came unstuck about the time when that proposition was given the critical scrutiny it deserved. So they got to re-think the reply and came up, cleverly, with the equally fictitious source: the people! “Governments are instituted among Men, deriving their just powers from the consent of the governed.” Ha!
Doubly deceptive, that: Firstly if one is governed, one cannot consent to it--the two are not compatible--and secondly the rights (or powers) assumed by governments greatly exceed the rights possessed by the governed, and therefore cannot possibly be derived from them. You have the right to rule yourself, but zero right to rule me, hence nobody you may appoint has the right to rule me, either. And a hundred million votes times zero is still zero.
Both of those alleged sources of the rights of rulers are therefore 100% bogus, and freedom will result when everyone grasps that simple truth. The reality was admitted by Mao: “Power [the right to rule in practice] comes from the barrel of a gun.” Nowhere else.
So whereas government toadies are understandably eager for us all to suppose that independent, inalienable rights do not exist, or that we have none, the fact is that we have all there are and that they have none. Rulers are totally fake; usurpers and pretenders. They are thugs with guns, policemen, courts and prisons; nothing else.
Lastly, let's repeat that the absolute self-ownership we each properly enjoy can be well expressed by this handy word “right”, but it's not something separate from the owner, as if it or they were a backpack of goodies we carry around. “Rights” can usefully be thought of as plural – the right to speak (or not), to property acquired without theft, to be left in peace, and so on, but all of them spring from the central one which is integral to our nature; if we live, we have the right to life, and to use it as we wish.
Only death can remove them, and only government can spoil their enjoyment.