Warning: SPOILERS for The Suicide Squad
Harley Quinn has grown significantly since her DCEU debut in 2016’s Suicide Squad – so why hasn’t she killed Jared Leto’s Joker? James Gunn’s The Suicide Squad marks Margot Robbie's third outing as Harley, but her cinematic future is uncertain, largely due to the mystery surrounding the Joker. Leto’s divisive interpretation of the clown was thought to be out of the picture, that is until his surprise cameo in Zack Snyder’s Justice League.
Harley was first introduced as a prisoner of Belle Reve Penitentiary who just wanted to be reunited with her abusive puddin', with Suicide Squad’s theatrical cut almost entirely glossing over the torture he subjected her to. In Birds of Prey, the couple broke up offscreen, allowing Harley to prove herself a formidable antihero who doesn't need the Clown Prince of Crime's protection. By the time of her latest mission with Task Force X, Harley has fully embraced her independence, with increased disdain for the Joker.
However, Harley’s relationship with her ex remains a huge unanswered question in the DCEU. Although the Snyder Cut isn't currently regarded as canon, the Joker's inclusion was another reminder that he is still out in the world. If Harley really has emancipated herself from him, and now seems firm against toxic relationships, then it's strange she hasn't tried to kill the Joker. This could be because she's secretly afraid to face the man who spent years tormenting her, but there's also the larger issue of the Joker's now tenuous position in the DCEU.
Birds of Prey saw Harley alter her tattoos to remove their connection to Mr. J In The Suicide Squad, Harley's jacket references Leto's Joker with the words "live fast, die clown" and her characterization supports this sentiment. She talks about recognizing red flags in love interests, killing Corto Maltese dictator Silvio Luna (Juan Diego Botto) upon learning of his murderous plans. This all originates from the Joker's abuse, suggesting she'd happily kill him if given the chance. Only, she doesn't appear interested in finding him. This could be because she doubts her independence is entirely true. Harley knows better than most how dangerous the Joker is. If she were to see him again, she may doubt her ability to defy his manipulation. This could fuel her desire to kill those who exhibit red flags - temporary replacements for her ex, until the day when she finally battles him.
The Joker is extremely jealous, ready to destroy any shred of happiness Harley finds without him. So where is he? Harley blew up ACE Chemicals and fought Black Mask's (Ewan McGregor) gang in his old hideout, which would surely gain the Joker's attention. Regardless of its place in the DCEU canon, the Snyder Cut's Knightmare sequence emphasized his survivalist nature, while killing off Harley. The Joker's specific involvement in her death was implied but never stated. If he did murder her, this would support the theory that Harley fears she is not yet strong enough to defeat him. However, The Suicide Squad further demonstrated she is an adept fighter, and Harley knows how the Joker thinks. This should tease an epic showdown, but no such project is currently in development, with Leto's Joker future undetermined and prior films abandoned.
In 2016's Suicide Squad, Harley fantasized about a normal life with the Joker. She has thankfully moved past this futile dream, but it's possible she isn't fully over him. Maybe Harley saw something genuine during their relationship that is yet to be explored, and this could ultimately be used to destroy him. Her precise feelings about him are uncertain, and her evolution will be incomplete without a confrontation. Until Harley Quinn kills the Joker, he poses a threat to her personal growth, always haunting her story.
