Why does Donald Trump keep going after Heidi Cruz?

Last night, Trump did another one of his patented retweets and, while this one wasn’t of a white supremacist, it was just as repugnant. 

This sexist attack on Heidi Cruz’s appearance came a day after Trump threatened to “spill the beans” on his opponent’s wife, in response to an anti-Trump super PAC ad that featured a naked photo shoot Melania Trump did for GQ. 

When Trump first attacked Heidi Cruz, I assumed it was in response to his dismal showing in the Utah primary—Trump has a habit of lashing out for media attention on nights when he loses. But why does Trump keep attacking Heidi, who has done nothing that should make her a central focus of his campaign, especially when Trump’s horrible favorability ratings with women will likely doom his hopes for the presidency? 

Trump is both incredibly insecure and incredibly thin-skinned, so it’s possible that he’s still angry about the Melania ads, even though Ted Cruz wasn’t responsible for them. It’s also possible that Trump is playing to his crowd at the expense of the larger electorate—that he’s doing what he does best, making his supporters froth at the mouth. Or it’s possible that, as my colleague Jeet Heer pointed out on Twitter last night, Trump is trying to sabotage his campaign, The Producers-style. Trump continuing to go after Heidi isn’t just repellant, it makes Ted Cruz look humane and classy by comparison.