Supreme Court Chief Justice John Roberts finds extreme partisan gerrymandering “unjust.” He doesn’t condone it himself. He doesn’t even defend it as constitutional. But he just issued the 5-4 majority opinion, with all five Republican appointees on one side and all four Democrats on the other, in a case that opens the door to politicians drawing district lines to favor their party without any fear of constitutional challenge. Given the extreme examples of gerrymandering in the two states whose maps were before the court — Maryland and North Carolina — not to mention plenty of others like Wisconsin and Texas, we shudder to imagine how badly political hacks with mapping software are about to fracture our democracy.

The court has never set constitutional standards for partisan gerrymandering before, but this ruling is nonetheless a sweeping one. Previously, the courts had held out some suggestion that they could police the extremes of the practice if only plaintiffs could provide the right legal theory or standard for the courts to apply.

But Mr. Roberts’ opinion dashes those hopes once and for all. He declared gerrymandering a purely political problem in need of a political solution, with no role for the courts whatsoever. He proffered a few profoundly unhelpful suggestions for limiting the practice, like federal legislation forcing states to adopt non-partisan redistricting commissions, state laws to establish them or voter initiatives to require them.

Well, not all states allow voter initiatives. (Maryland and North Carolina, perhaps not coincidentally, are among those that do not grant citizens that power.) Federal legislation? Maryland U.S. Rep. John Sarbanes’ election reform bill includes anti-gerrymandering legislation, and it has gone precisely nowhere in the Senate. And as for state lawmakers policing themselves, we have a bit of experience here in how difficult that is to achieve.

Maryland’s congressional districts are among the least compact and contiguous in the nation, and they were drawn with the stated intent of expanding Democrats’ majority in our house delegation from 6-2 to 7-1. Voters aren’t happy about that. The latest poll on the matter found that Marylanders want an independent commission rather than elected officials to draw the lines by a 73-20 margin. Gov. Larry Hogan, Maryland’s extremely popular Republican chief executive, has been pushing the cause of redistricting reform for years, and he won in a landslide over a Democrat who vowed at one point to monkey with the lines enough to make the delegation 8-0 if possible. Former Gov. Martin O’Malley, a Democrat who practiced the dark arts of gerrymandering a decade ago, has repented and supports an independent process. The lawsuit that eventually landed before the Supreme Court resulted in highly embarrassing testimony about what Maryland’s Democrats did to get the results they sought.

Yet has the General Assembly lifted a finger to change the process here? Not at all. They have sought to enact some legislative fig leaves in the form of a multi-state compact to abandon gerrymandering, but they refer to the idea of reforming on our own as “unilateral disarmament.” Even the prospect that Mr. Hogan will use his role in the process to tilt the scales more in Republicans’ favor — or at least to force Democrats to employ nakedly partisan tactics to block him — seems not enough to shame them into action. Politicians simply aren’t willing to cede a weapon they expect their party will eventually be able to wield in their favor, and voters, with many other issues on their minds, simply don’t throw politicians out for supporting skewed maps.

But the truth is that gerrymandered maps affect how every other issue is addressed. Elections in districts designed to produce a representative from one party or the other mean elections are decided based on which candidate can appeal to their party’s base in the primaries, not on which can appeal to the broadest segment of the electorate. In practice, that rewards extremism on both sides and punishes compromise. It thwarts democracy and prevents us from sensible solutions to the major issues of our time.

Russia used hackers in the last presidential election to stir extremists and spread doubts about our democracy. They need no longer bother. The Supreme Court just finished the job.