Cliff Sloan, a partner at the law firm Skadden Arps, filed an amicus brief in Gill v. Whitford on behalf of 15 historians of the founding era. Michael Waldman is president of the Brennan Center for Justice at New York University School of Law.

As the Supreme Court prepares to consider whether gerrymandering can ever be so partisan as to be unconstitutional, some defenders of the practice will contend that its long historical pedigree should immunize it from judicial review. But history tells a different story. Partisan gerrymandering is inconsistent with the democratic ideals enshrined in the Constitution, and Americans since the founding generation have vehemently denounced it. In the extreme form it takes today, with districts drawn to give the controlling party a stranglehold on power, gerrymandering represents an unprecedented threat to our democracy.

The case to be argued Tuesday, Gill v. Whitford, comes from Wisconsin. In 2011, Republicans, with control of the legislature and statehouse, rammed through a legislative map explicitly crafted to guarantee that the GOP would maintain its political power and could not be unseated by the ordinary operation of elections. The plan used sophisticated digital tools to ensure that Democrats could not regain control even if they won all swing districts. It was, in effect, a perpetual-motion entrenchment machine. A three-judge court held the plan unconstitutional.

Partisan gerrymandering — like racial gerrymandering and violations of the one-person, one-vote principle — has occurred at various times in American history. But it has been forcefully condemned as unconstitutional at every turn. Patrick Henry, for example, crafted a district to separate James Madison from his political supporters. But newspapers decried Henry's scheme as a violation of the right of a free people to choose their representatives. In the action that gave gerrymandering its name, Massachusetts Gov. Elbridge Gerry in 1812 signed a districting bill designed to give his party a decisive political advantage. Opponents objected that the law "inflicted a grievous wound on the Constitution" — it "subverts and changes our Form of Government" and "silences and stifles the voice of the Majority." The machinations of Henry and Gerry, adamant opponents of the Constitution, hardly embodied its spirit.

The next two centuries saw continued objections to partisan gerrymandering as a violation of our core constitutional principles. For example, in 1870, Rep. (and future president) James Garfield excoriated the practice and objected that "no man, whatever his politics, can justly defend" it. In 1891, President Benjamin Harrison condemned gerrymandering as a form of "political robbery." He declared that its "overthrow of majority control by the suppression or perversion of the popular suffrage" represented "our chief national danger." Other examples throughout our history abound.

All this vehement condemnation of gerrymandering as at odds with the Constitution should not surprise. The framers were keenly aware of the corruption of the English system of parliamentary elections, in which "rotten boroughs" and similar devices interfered with genuine democratic expression. Americans in the revolutionary age scorned the British concept of virtual representation, in which defenders claimed Parliament would act wisely even if it was not directly representative. Instead, they embraced actual representation as a central animating principle of the Constitution. Elected representatives would have close ties to their constituencies, and the assembly would be responsive to the popular, democratically expressed will. While omissions from the voting polity (such as race, gender and economic circumstance) now seem glaring, the commitment to actual representation — unimpeded by contrived barriers between the electorate and its representatives — was fundamental and widely shared. When colonists shouted, "No taxation without representation," they articulated a view of legitimate governance very much relevant to this case. And nobody thought that "representation" meant a ­government-imposed permanent minority status.

Madison understood the abuses that could come from state legislators trying to entrench their own faction. "Whenever the state legislatures had a favorite measure to carry, they would take care so to mold their regulations as to favor the candidates they wished to succeed," he warned at the Constitutional Convention. Inequality in legislatures would lead to inequality in congressional representation. "It was impossible to foresee all the abuses that might be made of the discretionary power," he said.

Partisan gerrymandering violates the framers' core principle of actual representation. It likewise conflicts with the First Amendment right to meaningful political speech and association, and with the 14th Amendment's extension of constitutional responsibilities to the states. Viewed through the prism of history, partisan gerrymandering is not an accepted and cherished feature of our American system. And the extreme gerrymanders we see today go dramatically further than anything we have seen in the past. They sabotage fundamental constitutional values. For those defending partisan gerrymanders, contrary to their sweeping claims, history is not on their side.