In siding against the Arizona state legislature, the Supreme Court avoided diluting the power of direct democracy in the US.

The court ruled in a 5-4 decision that a panel created by a 2000 anti-gerrymandering referendum had proper authority to redraw federal congressional districts. The dissenting conservative justices argued that the Elections Clause of the US Constitution only permitted state legislatures with the power.

“The history and purpose of the Clause weigh heavily against such preclusion,” Justice Ruth Bader Ginsburg wrote for the majority, “as does the animating principle of our Constitution that the people themselves are the originating source of all the powers of government.”

“The exercise of the initiative, we acknowledge, was not at issue in our prior decisions…we see no constitutional barrier to a State’s empowerment of its people by embracing that form of lawmaking,” she also wrote.

“Recall that when the Constitution was composed in Philadelphia and later ratified, the people’s legislative prerogatives—the initiative and the referendum—were not yet in our democracy’s arsenal,” Ginsburg noted.

Chief Justice John Roberts, writing the dissent, said that the people of Arizona were not permitted by the US constitution to have grievances addressed by “displacing their legislature.”

“They can follow the lead of the reformers who won passage of the Seventeenth Amendment,” he wrote. “Indeed, several constitutional amendments over the past century have involved modifications of the electoral process.”

At one point Roberts sarcastically referred to the organizers behind the Seventeenth Amendment movement—the move to have the people directly elect US senators—as “chumps.”

“Didn’t they realize that all they had to do was interpret the constitutional term ‘the Legislature’ to mean ‘the people’?”

Joining Roberts in dissent were Justices Antonin Scalia, Clarence Thomas, and Samuel Alito. Justice Anthony Kennedy , a Reagan-appointee, joined Ginsburg and the other three liberal Justices—Stephen Breyer, Sonia Sotomayor, and Elena Kagan.

Common Cause, a progressive public interest group, hailed the decision as a check on state lawmakers’ powers.

“A ruling in favor of the Legislature could have threatened 16 states with alternative redistricting systems and killed reform efforts in many more,” Kathay Feng, the group’s national redistricting director said, praising “the people’s power to take redistricting out of the smokey backrooms of state legislatures.”