Ask someone to quote from the U.S. Constitution, and you’ll likely hear the words “Congress shall make no law respecting an establishment of religion .” Ironically, though, if some of the Constitution’s framers had had their way, these words wouldn’t even have been in the document in the first place.

That’s because the phrase above is what opens the First Amendment. It and the nine amendments that follow are what make up the Bill of Rights, which some framers considered superfluous at best, and dangerous at worst.

Why? A good question to consider as we mark Bill of Rights Day. The first 10 amendments, after all, were adopted 225 years ago on Dec. 15, 1791. They constitute perhaps the most significant protection of liberty in the history of the world. How could any of the framers oppose their inclusion in the Constitution?

It wasn’t because they opposed the rights enumerated in the amendments. Quite the contrary, in fact. According to Joseph Postell, Ph.D., assistant professor of political science at the University of Colorado:

“The defenders of the Constitution argued that a bill of rights would undermine the idea of a government with limited powers. A bill of rights might betray the central principle of a written constitution as the product of a social compact, which affirms that all authority originally resides in the people and that the people create a government of limited and enumerated powers in a written constitution.

“To suggest, for example, that the liberty of the press is not to be infringed upon might imply that, without such a provision, the federal government would possess that power. The Founders feared that we might infer that they created a government with unlimited power and that the specific provisions in the Bill of Rights denote particular reservations of power from an otherwise unlimited government.”

Those arguing against the Bill of Rights had two other concerns. One was that the list could never really be complete. Wouldn’t people assume that any right not explicitly listed was considered unprotected? Hence the importance of the Ninth and 10th Amendments, respectively:

“The enumeration in the Constitution of certain rights shall not be construed to deny or disparage others retained by the people.”

“The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”

Their final concern was that a Bill of Rights might confuse people about the origin of their rights. The Declaration of Independence had already made it clear that our rights are inalienable because they are endowed by God. Government’s job isn’t to grant them, it’s to protect them. They felt a list of rights might inadvertently enforce the wrong idea.

Eventually, though, the opponents — most notably future President James Madison — changed their minds. Mr. Postell writes:

“The safeguard of individual liberty, Madison reasoned, must lie with the people themselves. It is the people who must be responsible for defending their liberties. And a bill of rights, Madison and his colleagues finally concluded, might support public understanding and knowledge of individual liberty that would assist citizens in the task of defending their liberties.”

There’s no question that those who opposed the inclusion of a Bill of Rights raised several valid concerns. But considering the threats that have arisen in the decades since, we can be thankful that many of our most important rights were indeed enumerated.

Our right to write and speak freely is under constant attack. Our right to keep and bear arms is frequently targeted. Our rights to be spared unreasonable searches and seizures, to be represented by counsel, to have a public trial — all have been challenged in the past and surely will be challenged in the future.

“I am constrained by a system which our Founders put in place,” President Obama once said. If that sounds as good to you as it does to me, thank the Bill of Rights.