Score one for the living Constitution. No, not gay marriage, which the framers couldn’t have imagined as a fundamental constitutional right. The winner is the referendum, which the framers would’ve hated but has been part of our government for more than a century.

The case, Arizona State Legislature vs. Arizona Independent Districting Commission, involved an obscure provision of the Constitution that was actually extremely important to those who drafted it during the long, hot summer of 1787. Article 1, Section 4 of the Constitution says that “The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof; but the Congress may at any time by Law make or alter such Regulations.”

The idea was that state legislatures, not Congress, would decide how congressional districts would be allocated within states. Congress retained the supervisory power to intervene just in case states failed to name representatives at all.

This provision of the Constitution is, needless to say, highly consequential. It gives state legislatures the power to create gerrymanders, which remain an ugly business to this day.

In 2000, voters in Arizona adopted an initiative to take the redistricting power away from the state legislature and give it to a nonpartisan, independent redistricting commission. The Arizona State Constitution allows for referendum-based initiatives that circumvent the ordinary state legislative process. And you can see why: Left to its own devices, legislatures might not want to give up the tremendous power to redistrict.

You see the catch coming, right? The Constitution says explicitly that the manner for elections shall be set “in each state by the legislature thereof.” An independent redistricting commission isn’t the legislature — indeed, that’s the whole reason it exists. Arizona’s move contradicted the explicit text of the Constitution.

Enter the idea of constitutional evolution.

James Madison and his colleagues shared an ideal of republicanism — which meant government by elected representatives, not government directly by the people. They would’ve considered government by referendum to be an example of radical democracy.

This isn’t mere speculation. In Federalist No. 55, Madison wrote that “in all very numerous assemblies, of whatever character composed, passion never fails to wrest the sceptre from reason. Had every Athenian citizen been a Socrates, every Athenian assembly would still have been a mob.”

But our modern conception of democracy differs markedly from Madison’s. In particular, the Progressive era saw a deepening distrust of legislatures, which could be corrupted by concentrated capital far more extensive than anything Madison imagined. The popular initiative, or referendum, is a classic Progressive tool — and it has become an important part of American democracy in many states.

If the Constitution is alive, it follows that it should be interpreted to allow changed conceptions of democracy to be applied to redistricting. If, to the contrary, the Constitution is frozen at the moment of its ratification, and should be read literally, then only the state legislature, not an independent commission, should be able to redistrict.

Writing for a five-justice majority, Justice Ruth Bader Ginsburg acknowledged that the framers were unfamiliar with the referendum, and she acknowledged that redistricting is classically a legislative task. But she went on to say that the Constitution is flexible enough to be interpreted to allow the change.

Ginsburg’s decision was probably correct. The truth is, we shouldn’t be asking whether the redistricting commission is consistent with Madison’s conception of democracy. We should be asking whether it’s consistent with ours. That’s the point of the living Constitution.

Justice Oliver Wendell Holmes Jr. put it best almost 100 years ago. The framers “called into life a being the development of which could not have been foreseen completely by the most gifted of its begetters. It was enough for them to realize or to hope that they had created an organism; it has taken a century and has cost their successors much sweat and blood to prove that they created a nation.”

The organism is alive. It now encompasses gay rights, and it encompasses a referendum to establish an independent redistricting commission. The sweat and blood isn’t just that of the Civil War soldiers whom Holmes had in mind — it’s ours, too.