A staff member of Donald Trump’s 2016 Presidential campaign filed a lawsuit in federal court in Florida on Monday, alleging that she experienced “racial and gender discrimination” while working for the campaign, that she was paid less than male and white colleagues, and that Trump once kissed her partially on the mouth, without her consent. The claim related to the kiss may prove difficult to verify. Four people said that the campaign worker, Alva Johnson, told them about the incident afterward, but two other people, who Johnson said were present at the time of the kiss, told me that they did not see it. In a statement, Sarah Sanders, the White House press secretary, denied that it had taken place.

The most legally significant aspect of Johnson’s suit may ultimately be something the complaint does not explicitly address: the pervasive use of nondisclosure agreements by Trump during his campaign and in his Administration. Johnson’s suit is at least the sixth legal case in which Trump campaign or Administration employees have defied their nondisclosure agreements. Three of those actions, including Johnson’s, were filed this month. Johnson, who was the campaign’s administrative field-operations director in Florida, signed a nondisclosure agreement that bars her from revealing any information “in any way detrimental to the Company, Mr. Trump, any Family Member, any Trump Company or any Family Member company.” Johnson’s attorney, Hassan Zavareei, said, “We expect that Trump will try to use the unconscionable N.D.A. and forced arbitration agreement to silence Ms. Johnson. We will fight this strong-arm tactic.”

The White House referred questions about the nondisclosure agreements to Michael Glassner, the chief operating officer of Trump’s reëlection campaign. He said in a statement, “The campaign takes our NDA agreements very seriously, and will enforce them aggressively if they are breached.” Johnson said that she considers the issues raised by her suit important enough to merit breaching the contract. “I am suing because my work holds the same value as the work of my white male counterparts,” Johnson said, in an interview. “I am suing because this predatory behavior should not be minimized, especially when committed by the most powerful man in the world.”

Nondisclosure agreements are routinely employed in the business world, but experts say that there is little comprehensive data on how they are used by Presidential campaigns. Hillary Clinton’s 2016 campaign reportedly required paid staff to sign such agreements, but Trump’s campaign seemed to use the agreements more widely, and even required unpaid volunteers to sign them. The practice has carried over to the Trump White House. The Washington Post reported last year that dozens of White House aides had signed N.D.A.s, a break in tradition from previous Administrations, which used the contracts more sparingly. White House interns have also reportedly been asked to sign the agreements as part of their mandatory “ethics training.”

Two former Trump advisers who had senior roles in the campaign said that workers were pressured into signing such agreements. Internal e-mails received by one of the former advisers repeatedly insist that “we must have that NDA.” The second adviser told me that Corey Lewandowski, the campaign manager, “was tasked by Mr. Trump to insure that anyone and everyone working with the campaign, whether salaried employee, volunteer, surrogate, or otherwise, execute a nondisclosure agreement or they would be terminated immediately. They strong-armed people to sign.”

The first adviser, who went on to hold a position in the White House, recalled that Stefan Passantino, the deputy White House counsel in charge of overseeing ethics, personally demanded a signature on an N.D.A. “They would not allow me to take the document off campus, would not allow me to e-mail the document to my attorneys. That’s where the red flags started,” the adviser told me. The adviser declined to sign, and felt that the decision had a negative impact on the adviser’s standing in the Administration. (Passantino did not respond to a request for comment.) A third former campaign official called the reports of workers being pressured to sign the agreements exaggerated. He said that staffers who declined to sign were not terminated, and noted that there were “always concerns” within the campaign about the enforceability of the agreements.

Johnson’s lawsuit will almost certainly face intense scrutiny, both because of her claims and because of the nature of the incident at the heart of the lawsuit. The complaint acknowledges that “forcible kissing might appear at first glance to be on the lesser extreme” of misconduct, but it argues that the interaction meets common-law definitions of battery, a legal term referring to harmful or offensive contact.

The lawsuit says that Johnson joined the Trump campaign in January, 2016, as the director of outreach and coalitions in Alabama, and that she held various positions in the ensuing months, eventually working as the administrative field-operations director in Florida. Johnson, who is African-American, asserts in her lawsuit that she was paid “substantially less” than other staff members with similar responsibilities because of her race and gender, and that campaign staffers made comments about race that made her uncomfortable. (One of those staffers disputed Johnson’s account, accusing her of having an “agenda.”) An analysis by the Boston Globe in June, 2016, found that female staffers on the Trump campaign were paid, on average, three-quarters what their male counterparts received.

Alva Johnson, wearing a white shirt and standing back left, at a rally with Donald Trump in Tampa, Florida, on August 24, 2016. Photograph by Loren Elliott / Tampa Bay Times / Getty

The incident in which Johnson said that Trump kissed her occurred during an event that she had helped organize in Tampa in August, 2016, according to the complaint. In an R.V. before Trump’s speech at the event, the complaint alleges, Trump took Johnson by the hand and leaned in to kiss her; she attempted to turn away, but, she claims, his mouth made contact with the corner of hers.

In her statement, Sarah Sanders said, “This accusation is absurd on its face. This never happened and is directly contradicted by multiple highly credible eyewitness accounts.” The two people who disputed Johnson’s account, Karen Giorno, a staffer, and Pam Bondi, a campaign surrogate, said that they had been close enough that they would likely have witnessed the incident. “I don’t even recall Alva being on the R.V.,” Giorno told me. (Photographs from the rally place Johnson inside the R.V.) Bondi, who said that she travelled with Trump extensively and never witnessed inappropriate behavior, added, “Had it happened, I feel I would have seen it, because I was there the entire time.”

Three of Johnson’s family members—her partner, her mother, and her stepfather—said that she told them about the incident immediately afterward, and recalled that she was in tears. Johnson said that at first she continued to go to work. In October, 2016, the Washington Post released audio of Trump saying, “I just start kissing them. It’s like a magnet. Just kiss. I don’t even wait.” At that point, Johnson said, she saw the incident with Trump as part of a pattern. She said that she took several sick days and consulted an attorney, whom she told in a text message that Trump had kissed her. She also spoke with a therapist, whose notes state that “she was having nightmares because of what happened.” The attorney, Adam Horowitz, advised Johnson to notify the campaign that she was resigning. Shortly afterward, the campaign sent Johnson a termination letter.