Donald Trump sues ex-senior aide for $10m over leaking information to media

Donald Trump is suing former top aide Sam Nunberg for $10m in back and forth litigation, only days before the presumptive GOP nominee will announce his running mate.

Nunberg, who left the campaign in August 2015 amid internal conflict, was sued by Trump in arbitration proceedings on 28 May over claims that he breached confidentiality.

The Republican operative, who after leaving Trump’s campaign announced he would support Ted Cruz, countersued on Wednesday in New York county supreme court, alleging that Trump was trying to silence him as part of a vendetta and trying to force proceedings into arbitration to shield “the ridiculous nature of the Trump campaign’s irrational and vindictive assault against me”.

In an affidavit obtained by the Guardian, Nunberg alleges the suit “is retaliation for my change of political opinion and the free exercise of my first amendment right to abandon my political backing of Mr Trump and to endorse and associate with US senator Ted Cruz publicly”.

In an interview, Nunberg’s lawyer, Andrew Miltenberg, told the Guardian that Trump is alleging that his former aide “violated confidentiality after he was no longer employed”. Miltenberg said it was “a vendetta” and added “we think it had everything to do with an important Trump campaign manager came out and supported Ted Cruz”.

In particular, Miltenberg said that the Trump campaign is alleging that his client leaked a New York Post story about a public spat between the then campaign manager Corey Lewandowski and press secretary Hope Hicks. The two reportedly engaged in a public argument on a weekday night in midtown Manhattan, with Hicks screaming: “I’m done with you.”

The affidavit includes a denial by Nunberg that he provided the New York Post with a story about what he described as a “lovers’ quarrel” and describes Lewandowski and Hicks engaging in “a sordid and apparently illicit affair”.

Nunberg also states in the affidavit that his removal from the campaign happened after Lewandowski “began a campaign to oust any competing voices within the developing campaign”. Nunberg was fired by Trump after past racially insensitive social media posts of his emerged in August 2015.

In the Trump campaign’s arbitration claim against Nunberg, they accuse the former aide of disseminating information about the campaign to a number of news outlets with “both intent and malice to the detriment of his campaign and for his own personal benefit”.

The Trump campaign did not respond to a request for comment; nor did Lewandowski.