While lawyers for the US president argue the subpoenas are ‘cynical’, the says they could help shine light on a $10bn defamation case.

United States President Donald Trump has called on a federal court to deny a motion by the to subpoena members of his immediate family, as part of a $10bn lawsuit over a documentary the broadcaster aired.

On Friday, lawyers for Trump argued that the had embarked on a “politically charged discovery campaign” by seeking to compel testimony from Trump’s eldest son Donald Trump Jr, his first daughter Ivanka Trump and his son-in-law Jared Kushner.

Trump’s team appealed to the court to reject the ’s motion, comparing it to a fishing expedition that goes beyond the scope of the case.

“This case concerns a narrow wrong — the ’s deliberate splicing together of two passages of President Trump’s January 6, 2021, speech spoken nearly fifty-five minutes apart,” Friday’s court filing said.

“Rather than litigate that narrow claim, the has attempted to pursue a sweeping investigation disguised as discovery.”

The case began in December, when Trump announced he would sue the over an episode of the documentary series Panorama, which chronicled the Republican leader’s path to a second term as president.

Part of the documentary focuses on the events of January 6, 2021, the day the results of the 2020 election were to be certified. Trump had lost that election but falsely claimed his defeat was the result of fraud.

At a speech in front of the White House on that day, he repeated the unfounded accusation that the election had been “rigged” to a rally of his supporters, some of whom participated in an attack on the US Capitol in the hours afterwards.

The Panorama episode included snippets from Trump’s speech, and critics argued that two sentences from his address had been edited together to sound like one continuous quote.

The first line was: “After this, we’re going to walk down, and I’ll be there with you, we’re going to walk down.” The second came from later in the speech: “And we fight. We fight like hell.”

Though the apologised for the editing and took the Panorama episode down from its platforms, Trump nevertheless filed a multibillion-dollar lawsuit accusing the broadcaster of defamation.

The has denied that charge and pledged to fight the lawsuit in court. The case is currently being heard before the US district court in southern Florida.

As part of its defence, the has sought testimony from figures close to Trump, to establish his thoughts and actions on the day of the January 6 attack.

It pointed out that both Donald Trump Jr and Ivanka Trump were present at their father’s speech, and that they spoke to the president and his inner circle as the violence erupted at the Capitol.

Text messages released by the US Congress show Donald Trump Jr urged his father’s chief of staff to “condemn this sh**”, a fact cited in the ’s motion.

While Kushner was not present at the White House, the maintains that his role as Trump’s adviser would also help establish the facts of that day.

Lawyers for the broadcaster say that, after speaking with congressional leaders, Kushner drafted “a proposed statement” for Trump to present, “which would have condemned the use of violence”.

The testimony of Trump Jr, Ivanka Trump and Kushner can help illustrate the president’s “burden to prove that it would be materially false to imply that he incited violence on January 6”, according to the ’s motion.

But, the motion added, the has been unable to serve the three family members with subpoenas due to the presence of their US Secret Service protection.

The reportedly attempted to deliver subpoenas to Ivanka Trump and Kushner at their residence in May, only to face Secret Service agents who said they were not authorised to accept the documents.

Likewise, that same month, the was unable to hand Trump Jr a subpoena at Trump Tower in New York. It has therefore asked the court for permission to use certified mail to deliver the documents instead.

But in Friday’s court filing, Trump’s lawyers accused the of carrying out a “cynical” campaign that involved the “harassment of the President’s family, associates, staff, officials, and others”.

It also called the ’s efforts “a boundless re-investigation of the events that occurred on January 6, 2021”.

The filing suggests that any interactions involving Ivanka Trump and Kushner are “subject to the executive privilege” of the presidency, since the husband-wife duo served as adviser and senior adviser to Trump, respectively.

Trump has made sweeping claims to executive privilege throughout his two terms in office.

Just this month, the US Department of Justice issued a memo saying such privilege shielded communication even with private advisers who worked outside the executive branch, effectively declaring interactions with companies and private individuals off-limits for subpoenas.

Critics fear the memo will be a hurdle to government transparency under Trump — and may even prevent Congress from accessing investigative materials.

Senator Adam Schiff of California framed the memo as an insurance policy against congressional oversight, should the Republican Party lose its majorities in Congress during November’s midterm elections.

“This latest opinion should be seen as a partisan measure to insulate the president and his corrupt activities from Congressional subpoenas when the majority flips,” he wrote in a statement on August 11.

The federal court in southern Florida has yet to rule on the ’s subpoena requests.

The , meanwhile, has sought to have the entire case tossed, on the basis that Trump is attempting to dampen free speech.