Summer Zervos was one of 11 women who spoke out against US president Donald Trump last year, accusing him of sexual assault.
In January, Zervos, a former contestant on Trump’s reality television show The Apprentice sued the US president, saying that he had defamed the women who came forward, herself included.
Trump called the women “liars”, who had made “phony” accusations while on the campaign trail last year.
Late on Tuesday evening, Trump’s lawyer Marc Kasowitz said Zervos’ action is “a politically-driven” one.
She can’t hold Trump liable for engaging in “political speech in the context of a public debate,” which is protected by the First Amendment right to freedom of expression, he added.
Kasowitz wrote in the in 36-page legal filing:
Mr Trump was merely defending his character and qualifications for office from the false attacks Ms Zervos levelled against him just a few weeks before the presidential election.
Kasowitz added that Zervos’ lawsuit “is based on allegations of events that never occurred”.
Currently a California-based restaurant owner, Zervos accused Trump in October 2016 of aggressively kissing her and groping her breasts during a 2007 meeting.
Trump has denied her accusations.
Zervos decided to go public after the Access Hollywood tape was released, where footage showed Trump bragging about being able to grab women “by the pussy.”
Asked about Zervos’ defamation case last month, Trump called it “made-up stuff”.
“It’s totally fake news,” he added.
Trump’s lawyers have asked for the dismissal of Zervos’ suit, or a stay in the case while Trump is president, insisting that the claim is a civil action and therefore unrelated to his official duties as president.
However, Zervos’ lawyers responded by referring to a US Supreme Court ruling that allowed Paula Jones to bring a sexual harassment suit against president Bill Clinton while he was in office.
“Mr. Trump knowingly, intentionally and maliciously threw each and every one of these women under the bus, with conscious disregard of the impact that repeatedly calling them liars would have upon their lives and reputations,” they added.
Zervos has sent a subpoena to the Trump campaign requesting documents concerning “any woman alleging that Donald J. Trump touched her inappropriately”.
Trump’s lawyers are likely to try to avoid complying with the subpoena, Stephen Vladeck, a professor at the University of Texas School of Law told Vox.
The subpoena remains on hold while Trump’s lawyers seek to have the case dismissed.