THE STORY OF Harvey Weinstein is partly a story of secrecy: how the Hollywood producer managed to keep his habit of sexually harassing and assaulting women under wraps for so long. The answer, at least in part, involves Mr. Weinstein's use of confidential settlements and non-disclosure agreements that kept his victims and employees from speaking out.

In this sense, Mr. Weinstein's story is far from unique. Powerful men engaged in sexual misconduct often use similar legal tools to bury controversy — as did both Fox News's Roger Ailes and Bill O'Reilly, who negotiated multimillion-dollar settlements to ensure their victims would remain silent. Even now, with the appalling behavior of these men in the public record, some victims remain unable to make their experiences public. Mr. Weinstein's former assistant has chosen to break her confidentiality agreement to speak out, but took the risk of doing so only after news of her employer's behavior became public.

Several types of agreements can prevent a public accounting of harassment and assault. Some employers — including the Weinstein Co. and Fox — require employees to sign away their rights to criticize the company in public or to adjudicate disputes before a judge, rather than in private arbitration. After leaving Fox, former anchor Gretchen Carlson fought to make her harassment case against Mr. Ailes public rather than bring her complaints to arbitration as required by her employment contract. And Mr. Weinstein's employees have now publicly requested that the company's board free them from their non-disclosure agreements to allow them to speak openly about what took place.

Many of the women harassed or assaulted by Mr. Weinstein or Mr. Ailes reached settlements under the condition that they never make their experiences publicly known. While federal law places some limitations on the scope of non-disclosure agreements written into employment contracts, corporations have greater leeway to restrain speech through confidentiality provisions in settlements.

Ms. Carlson is now pushing for federal legislation to prohibit employers from mandating private arbitration for civil rights complaints. On the state level, lawmakers in New York, New Jersey and California plan to introduce legislation to block courts from enforcing non-disclosure agreements in employment contracts and settlements that prevent employees from speaking out about sexual harassment. Many states have similar laws preventing settlements that conceal information on "public hazards," and California already prohibits such agreements in cases involving rape and sexual assault.

Some victims of sexual harassment and assault may desire settlements that allow them to retain their privacy. Legislators should be mindful of these differing needs. Perhaps, as University of Chicago law professor Daniel Hemel suggests, lawmakers could allow confidentiality agreements with a one-sided opt-out provision: The assailant would be barred from speaking publicly unless the victim chose to speak first.

Laws alone can't change a culture in which powerful men feel entitled to prey on those around them. But reducing secrecy would be an important step toward holding predators accountable and diminishing their opportunity to transgress multiple times.