On Monday, Alva Johnson, a former campaign staffer who accused President Trump of sexual misconduct and pay discrimination in a lawsuit this year, filed a motion asking a judge to formally expand the scope of her suit so that others, including former campaign and White House aide Omarosa Manigault Newman, may sign on.

Johnson, an Alabama woman who worked for the Trump presidential campaign for all of 2016, alleged in February that Trump kissed her without her consent at a campaign rally in Florida. Johnson, who is black, also alleged in the original lawsuit that Donald Trump for President Inc. paid her less than her white and male colleagues with similar job titles and responsibilities.

“This case is about two things: Donald Trump’s predation, and his campaign’s discrimination against women and people of color,” Hassan Zavareei, the lead attorney representing Johnson, said in a statement.

In a statement, Manigault Newman said the suit addresses the “gender pay gap” that exists not just between women, but between people of color and their white counterparts. She joined, she said, to “level the playing field in the political arena.”

“While I strongly suspected I was subjected to pay discrimination while with the Trump Campaign, I have since seen expert analysis confirming this to be true. The numbers don’t lie,” Manigault Newman said. “After nearly 20 years inside the Beltway, working for two White Houses and countless political campaigns, I’ve never witnessed such egregious violations as I did during my time under the leadership of Donald Trump and Mike Pence.”

The White House previously dismissed Johnson’s sexual misconduct allegation as “absurd on its face.” In a separate motion filed last week, the campaign and Trump asked the court to dismiss Johnson’s pay discrimination lawsuit because it lacked substantive evidence for its claims, including proof that the only factor separating staffers was their sex.

Monday’s filing by Johnson’s attorneys, which asks the judge to certify the suit as a collective action, provides more information about those pay discrimination allegations. It includes an initial pay study conducted by Phillip M. Johnson, an economist and managing director of Econ One Research, which found that, on average, female campaign staffers were paid 18.2 percent less than their male counterparts between May and December 2016.

That analysis, which excluded a smaller cohort of higher-paid employees in “senior leadership roles” so as not to skew the data, was conducted using publicly available pay data maintained by the Federal Election Commission, according to court documents. It looked at pay for 77 female and 151 male staffers. The motion notes that more-detailed payment data could be obtained through discovery, such as job description, race, gender, age and payment justification.

Monday’s filing is the next step toward proving that the campaign participated in sex discrimination, Zavareei said, which is a violation of the Equal Pay Act. The pay study also observed a pay gap of nearly 50 percent among male and female staffers in top-ranking jobs.

“The Trump campaign has never discriminated based on race, ethnicity, gender, or any other basis,” Kayleigh McEnany, National press secretary for the campaign, said in a statement Monday. “Any allegation suggesting otherwise is off base and unfounded.”

In an interview with The Post, Zavareei called pay discrimination one of the most “insidious problems in our society.” A separate analysis by the Boston Globe in 2016 found that in April of that year, women working for the campaign were paid less than men by a gap of 35 percent.

“The fish rots at the head here,” Zavareei said. “If you have the president and his campaign discriminating against women … then that sets the tone for what happens in the commercial world and other sectors of government.”

He said Manigault Newman’s willingness to join the lawsuit as a “high-ranking female campaign staffer” strengthens the case. Zavareei said he is hopeful that her participation will empower other female staffers to join.

If the judge grants Johnson’s motion, her legal team will be able to obtain contact information for all the Trump campaign’s female staffers and invite them to participate in the suit.

Zavareei said it is his understanding the Trump campaign required some, if not all, staffers to sign nondisparagement agreements as a prerequisite to employment and has pressured them to keep quiet. Other staffers, he said, are working in the White House or for the president’s reelection campaign and may not be inclined to join.

“We’re hopeful there will be others,” he said.

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