Donald Trump can’t stop bashing Alicia Machado and it’s dragging his campaign down.

Perhaps the Clinton campaign’s shrewdest insight into Donald Trump is that he is easily baited. When he feels personally slighted, he can’t let go of a subject but keeps on fighting. During Monday’s debate, Clinton laid some juicy bait for Trump by bringing up the way he had mistreated Venezuelan beauty queen Alicia Machado. Rather than showing any judgement by apologizing and moving on, Trump jumped on the bait like a hungry rat. Since debate night, he’s attacked Machado constantly. On Bill O’Reilly’s show last night, the Republican nominee portrayed himself as the victim of an ungrateful employee he tried to help. “I saved her job because they wanted to fire her for putting on so much weight ... it is a beauty contest,” Trump told O’Reilly.

Trump also hinted that there would be more personal attacks, saying, “A lot of things are coming out about her.” This is an allusion to a smear campaign against Machado being conducted by Trump’s media allies, which have been trawling Latin American tabloids for sensationalistic and often false stories about the former Miss Universe. Rush Limbaugh called her a “porn star Miss Piggy.” Some of Trump’s surrogates have also taken the bait. On Tuesday, Newt Gingrich told a Republican gathering, “You are not supposed to gain 60 pounds the year you’re Miss Universe.”

For a campaign that is struggling with a gender gap, attacking a woman for being overweight might seem like a self-destructive move. After all, according to a PPP poll, 65 percent of voters find Trump’s comments about Machado to be inappropriate and only 17 percent find them appropriate. Given these numbers, it’s puzzling that the Trump campaign has doubled down on the message “No Fat Chicks.”