Justice Ruth Bader Ginsburg has decided to take a stand against a major party’s presidential candidate in a way that she—and arguably no prior justice—has ever done before. Over the course of several interviews, the justice has spent the last few days hammering Donald Trump for his reckless campaign and outrageous policies, suggesting that a President Trump would pose a serious danger to the republic. Her explicitly political statements set off a familiar firestorm about whether Ginsburg had “crossed the line,” sending the conservative blogosphere in particular into howling fantods. Critics on the left and right have criticized Ginsburg’s comments as explosive, unprecedented, and unethical.

They are. That’s the point.

To recap the controversy, Ginsburg’s campaign began with a light jab at Trump in a Thursday interview, in which the justice admitted she didn’t “want to think about” the possibility of a Trump presidency. Then, on Friday, Ginsburg told the New York Times’ Adam Liptak, “I can’t imagine what this place would be—I can’t imagine what the country would be—with Donald Trump as our president.” Days after her Times interview, Ginsburg told CNN’s Joan Biskupic that Trump is a “faker” with “no consistency” and she criticized his refusal to release his tax returns. “He really has an ego,” she said (correctly and understatedly).

There is really very little to debate about the ethics of Ginsburg’s comments. They were plainly a violation, the kind of partisan partiality that judicial ethics codes strive to prevent. But Ginsburg, who is a quietly canny judicial and political strategist, surely knows that her comments were an ethical error. That leads to a fascinating question: Why would the justice risk her reputation and good standing—and even her power to hear cases involving Trump—for a few quick jabs at the candidate? The answer, I suspect, is that Ginsburg has decided to sacrifice some of her prestige in order to send as clear a warning signal about Trump as she possibly can. The subtext of Ginsburg’s comments, of her willingness to comment, is that Trump poses an unparalleled threat to this country—a threat so great that she will abandon judicial propriety in order to warn against looming disaster.

To be clear, what Ginsburg is doing right now—pushing her case against Trump through on-the-record interviews—is not just unethical; it’s dangerous. As a general rule, justices should refrain from commenting on politics, period. That dictate applies to 83-year-old internet folk heroes as strictly as it applies to anybody else who dons judicial robes. The independence of our judiciary—and just as critically, its appearance of impartiality—hinges on a consistent separation between itself and the other branches of government. That means no proclamations of loyalty to any candidate, or admissions of distaste of any other.

You don’t need to be a judicial ethicist to see the wisdom of this principle. Trump is a litigious man; should he take a campaign-related lawsuit to the court, Ginsburg will now surely be pressed to recuse herself. And of course, more significantly, these calls for recusal would accompany every case involving a possible Trump administration. (Through the Department of Justice, the executive branch is tasked with defending federal laws and presidential actions in court.) Moreover, Ginsburg’s comments all but begged Trump to respond—which he did on Tuesday, with a surprisingly coherent rebuke.

“I think it’s highly inappropriate that a United States Supreme Court judge gets involved in a political campaign, frankly,” Trump told the New York Times. “I think it’s a disgrace to the court and I think she should apologize to the court. I couldn’t believe it when I saw it. … It’s so beneath the court for her to be making statements like that. It only energizes my base even more. And I would hope that she would get off the court as soon as possible.”

This rejoinder transforms the Ginsburg-Trump feud from a one-sided roast to a full-on debate. That is quite alarming, because in the United States, politicians and judges are not supposed to debate. Will Ginsburg respond? If she does, her actions will severely tarnish her legacy; if she doesn’t, she may look craven. Best-case scenario, this feud gives Trump license to drag Ginsburg through the mud and turn her into an election issue; worst-case, it delegitimizes Ginsburg’s judicial authority. And since Ginsburg’s criticisms will change exactly zero minds, the benefits of the debate will flow almost exclusively to Trump.

Ginsburg’s comments also set a dark precedent for other justices with equally strong political inclinations—in other words, every justice ever to sit on the bench except David Souter. I can’t imagine, for instance, that Notorious RBG–loving liberals would be as pleased to hear Justice Samuel Alito bash Hillary Clinton as they are to hear Ginsburg diss Trump. Had Ginsburg said something similar about Mitt Romney, or John McCain, or George W. Bush, her slights would have been profoundly inappropriate. Here, progressives might point out that Sandra Day O’Connor declared her distaste for Al Gore on election night in 2000. (When Gore appeared to have won Florida, she reportedly said aloud, “This is terrible.”) But her comment that night was neither as deliberate nor as brazen as Ginsburg’s; it was more of a slip than an intentional campaign to impugn her disfavored candidate’s character.

Given all of these compelling reasons that Ginsburg should have refrained from speaking her mind about Trump, why did she take the risk? It seems clear that Ginsburg has made a very conscious decision to cash in her political capital after years of holding her fire. The justice is 83, and while she remains healthy and sharp, she probably won’t sit on the court for much longer. She won’t be impeached—Supreme Court justices must do much worse to suffer that sorry fate—and she can’t be voted out. In effect, Ginsburg has nothing to lose but her good name. And that, it seems, is what she has decided she is willing to risk if it might potentially rally her admirers against Trump’s looming peril.

After all, Donald Trump is not an ordinary presidential candidate, or an ordinary Republican. He is a racist, misogynistic, xenophobic bigot. He has proposed banning Muslims from entering the United States; called Mexican immigrants rapists and criminals; supported the deportation of 11 million undocumented immigrants; routinely treated women with sexist disdain; advocated for torture of suspected terrorists; and generally dismissed the rule of law. He is, as my colleague Jamelle Bouie lucidly explained, a fascist, in a completely different category from previous Republican presidential nominees.

Romney and McCain had qualities and policies that Ginsburg surely loathed as well. But they always had America’s best interests at heart. That is altogether untrue of the sinister and self-interested Trump. For Ginsburg to treat Trump with the same respect—that is, complete silence—that she afforded previous Republican nominees would acquiesce to the premise that his candidacy is just like theirs. It would suggest that this is an election like any other, a run-of-the-mill election rather than a battle for America’s soul. It would legitimize a fascist.

And so, sensing the menace that Trump undoubtedly poses to her country, Ginsburg abandoned judicial propriety to wrestle in the mud with a candidate she detests. It is not pretty, it is not pleasant, and it may not even be that smart. But it may be the one thing the justice can do to help prevent a President Trump. And to her mind, that alone may make it worthwhile.

Read more Slate coverage of the 2016 campaign.