Chief Justice John G. Roberts Jr. at the Capitol in December 2018. (Jabin Botsford/The Washington Post)

Joshua A. Douglas is a law professor at the University of Kentucky College of Law. He is the author of “Vote for US: How to Take Back Our Elections and Change the Future of Voting.”

The Supreme Court ruled in June that federal courts are closed to claims of partisan gerrymandering. But never fear, Chief Justice John G. Roberts Jr. wrote for the majority: “numerous [states] are restricting partisan considerations in districting through legislation,” either by legislative enactment or ballot initiative.

That alternative method to solve the problem is no saving grace. Many states simply do not allow ballot initiatives. In others, entrenched politicians will not give up their power easily.

Consider what happened this month in New Hampshire. The New Hampshire legislature passed a bipartisan bill that would have created an independent redistricting commission for that state. But Gov. Chris Sununu, a Republican, vetoed the bill, an act that was fundamentally anti-democracy. Instead of agreeing with most New Hampshire voters and legislators that gerrymandering harms our democracy, Sununu instead chose to keep the power to gerrymander with self-interested politicians.

Sununu’s veto was a pure power grab and nothing more. New Hampshire, like most other states, allows its legislature to redraw district lines for the state legislature and Congress after each census, which occurs every 10 years. When legislators have the power to draw the lines, they usually act in predictable ways, drawing district boundaries to ensure their own reelections.

The New Hampshire proposal would have taken much of that power away from the legislators. Instead, the law would have created a 15-member advisory commission comprised of five Democrats, five Republicans and five unaffiliated individuals. The selection process for these commissioners was eminently fair, with each side essentially allowed to choose commissioners nominated by the other party; the 10 chosen partisan commissioners would select the remaining five unaffiliated commissioners.

The commission would meet and redraw district lines using a set of criteria that emphasized fairness to all constituents. At least nine of the 15 commissioners would have to approve a map, ensuring that no one political party could control the outcome. The state legislature would then have the final say on adopting the new maps.

Sununu wanted no part of this fair process, even though the proposed law passed the state House by a vote of 218 to 123 and passed the state Senate through a voice vote — meaning that members of both parties supported the measure.

In his veto statement, Sununu claimed the commission would be “unelected and unaccountable to the voters.” Nonsense. Don’t we want those who craft election rules to be impartial and not subject to the political whims of the day? To use one of Roberts’s analogies, those who make the rules should be umpires, not tied to one team or the other. There is nothing fair about leaving the ability to draw the lines to those who are most interested in the political makeup of those districts.

Sununu also claimed in his veto statement that “issues of gerrymandering are extremely rare in New Hampshire.” Again: nonsense. Like many other states, New Hampshire has suffered from gerrymandering for decades. In 2012, for instance, Democrats won a clear majority of total votes for Senate candidates but secured only 11 of the 24 Senate seats thanks to the gerrymandered district map that Republicans drew in 2011.

Yet what’s perhaps most confounding about Sununu’s veto is that Democrats, not Republicans, are in the majority in the New Hampshire legislature. Democrats, therefore, supported a measure that went against their own self-interest and would reduce their power in the future, assuming they retain majority control in 2021 for the next round of redistricting. Democrats — and many Republicans — instead put country over party and democracy over self-interest in supporting the commission. Sununu wanted none of it.

The brazen political move is in line with similar Republican efforts to thwart other independent redistricting commissions. Republicans in Michigan are (again) challenging that state’s new redistricting commission, passed overwhelmingly by the voters in 2018. Missouri legislators, too, are trying to undo aspects of its voter-approved commission.

The public overwhelmingly opposes partisan gerrymandering and overwhelmingly supports independent redistricting commissions. That’s why voters have waged a grass-roots movement to sustain our democracy. Entrenched politicians want to throw that progress by the wayside to keep themselves in power.

The pushback to independent redistricting commissions in New Hampshire and other states shows the folly in Roberts’s salvo that all is not lost because states can enact their own meaningful reforms to combat partisan gerrymandering. They can’t do so when self-serving politicians stand in the way.

The voice of voters, not entrenched politicians, must win the day. We must all demand it — with our voices, and when necessary, our votes.

Read more:

The Post’s View: The court’s gerrymandering decision is understandable — but wrong. Here’s what’s next.

Alex Keena, Michael Latner, Charles Anthony Smith and Anthony McGann: Here’s how to fix partisan gerrymandering, now that the Supreme Court kicked it back to the states.

Charles Lane: Progressives should be glad they lost the Supreme Court gerrymandering case

Marcy Kaptur: My district was gerrymandered. The damage is easy to measure.