One accomplishment of Donald Trump’s campaign for president has been to reveal that American politics had not previously been as degraded as some of us thought. Before he entered the scene, many of us assumed our politics were in the gutter. We’d passed through Nixon, Gary Hart, Willie Horton, and Bill Clinton’s impeachment. We saw the 2000 whisper campaign about John McCain fathering a black child and the spectacle of vice presidential candidate Sarah Palin whipping crowds into a völkisch frenzy. Trump, however, reminds us that even in the midst of all this debasement, certain norms remained in place, invisible and taken for granted until he started going after them with a sledgehammer.

See, for example, the trashing of Heidi Cruz at the hands of Trump and his supporters. I’m not just talking about Trump’s Twitter mockery of Ted Cruz for not having a hot trophy wife, though that’s also a new low in modern political life. I mean the Trump-inspired Twitter pile on over Heidi Cruz’s mental health. In the past, candidates’ psychiatric histories have come under scrutiny—the paradigmatic case was Thomas Eagleton, who briefly served as George McGovern’s running mate—but the mental health of spouses generally has not. No one, after all, benefits from a situation in which all politicians’ relatives are subject to a reputational free-for-all. No one, that is, except Trump.

This latest romp through the mud began, to be fair, with a scummy attack on Trump’s wife, Melania. As you probably know by now, an anti-Trump super PAC put out an online ad, targeted to Mormons, attempting to shame Melania for posing nude for British GQ. Trump responded with a Twitter threat to “spill the beans” on Ted Cruz’s wife. It’s not clear whether Trump was actually talking about Heidi Cruz’s history of depression, or whether he was just trolling for dirt. Whatever he intended, his tweet ensured that his rabid online followers would go after her.

Heidi Cruz’s depressive history was hardly a secret; BuzzFeed reported on it last year. On the night of Aug. 22, 2005, police found her sitting, head in hands, on the grass near an Austin, Texas, freeway. She wasn’t intoxicated, but an officer on the scene concluded that she was a danger to herself, apparently because she was so close to traffic. “About a decade ago, when Mrs. Cruz returned from D.C. to Texas and faced a significant professional transition, she experienced a brief bout of depression,” an adviser to Ted Cruz told BuzzFeed’s McKay Coppins and Megan Apper. “Like millions of Americans, she came through that struggle with prayer, Christian counseling, and the love and support of her husband and family.”

If you’re a normal person, it’s easy to sympathize with Heidi Cruz’s misery, and not just because Ted Cruz is her husband. As BuzzFeed reported, she’d been a rising star in George W. Bush’s White House before walking away from a job she loved so that Ted could pursue his career in Texas. She ended up at Goldman Sachs’ Houston office, where she was the only woman. “She … quickly found that Houston’s finance scene was considerably less accommodating to high-powered women than those of Washington or Manhattan,” wrote Coppins and Apper. (Her culture shock recalls that of Hillary Clinton, who gave up her promising career in D.C. to follow her husband to Arkansas, where she felt marooned.)

The Cruzes knew Heidi’s brief breakdown was going to come out during the course of the campaign, but they had no reason to suspect that their opponents would make much of it. After all, anyone who smeared Cruz for his wife’s mental illness would be subject to widespread opprobrium. Further, Cruz’s greatest weakness is his repulsive personality. His apparent loyalty to his intelligent, complicated wife may be his lone redeeming quality; highlighting her struggles only humanizes him.

But Trump doesn’t think in terms of ordinary political strategy. His thuggery is blunter. He seeks to intimidate, hurt, and humiliate his opponents in any way he can, even if it costs him personally. Besides, the Voldemort-like power he derives from publicity, even bad publicity, immunizes him from public shame.

This is awful for Heidi Cruz, whose marriage to Ted Cruz has already cost her quite a lot emotionally. It’s also terrible for Hillary Clinton, Bill Clinton, and anyone Bill Clinton has slept with since leaving office. Before Trump, the conventional wisdom was that Bill Clinton has probably continued having affairs in his post-presidential years but that it wasn’t in the interests of Hillary’s enemies to publicize them. Doing so would leave them looking tawdry and create sympathy for Hillary, whose approval ratings hit a high point during the Monica Lewinsky scandal.

Trump doesn’t appear to care about approval ratings. He seeks to destroy people who stand in his way, especially women, even if he looks disgusting doing it. Trump’s attacks on Heidi Cruz are unlikely to hurt her husband politically, but they’re surely painful personally. And when he rips into the Clintons’ marriage, it probably won’t help him win the election. But it will make Hillary suffer, and that, for Trump, might be its own reward.

Read more Slate coverage of the GOP primary.