A spokesperson for special counsel Mueller says they will decline to comment on Nunberg's allegations.
Sam Nunberg called reporters and TV news programs on Monday and said live that he'd gotten a grand jury subpoena as part of Mueller's investigation asking for communications with other people in the Trump orbit - but that he would not comply.
"You know what, if Sarah Huckabee wants to start debasing me - she's a joke", Nunberg said.
Mr. Kushner, Mr. Trump's son-in-law and a senior transition adviser, met at Trump Tower with Sergey I. Kislyak, the Russian ambassador to Washington at the time, and discussed setting up a back channel to communicate with Moscow during the transition - circumventing American diplomatic channels normally used during a presidential transition. He said the scope of what he was being asked for made him agree with Trump's characterization of the investigation as a "witch hunt".
On MSNBC with Katy Tur, Nunberg raised eyebrows by suggesting that some amount of impropriety may have happened during the campaign. "I'm not going to give them the excuse to throw me into jail because I won't respond to a question".
At one point during Monday's press marathon, CNN's Erin Burnett asked Mr Nunberg if he had been drinking, noting that she smelled alcohol on his breath. Russian Federation denies the allegations and Trump says there was no collusion between Moscow and his campaign. "He talked about it for a week before, and I don't know why he did this", Nunberg claimed. She said the subpoena was "reasonable" and that Nunberg would do "more service" by testifying than by refusing, because a refusal carried an appearance of wrongdoing.
For weeks now, the Russian and Trump collusion story has been the subject of news highlight reels and the topic of conversations for many individuals.
An adviser to the United Arab Emirates is reportedly cooperating with special counsel Robert Mueller.
To appreciate what a wide mandate Robert "straight-arrow" Mueller has been given, just cast your mind back over the almost twenty people he has indicted so far, and consider especially what they have been indicted for.
If Mueller is getting closer to finding out, Nunberg won't be helping the process: He promised to tear up the subpoena on Bloomberg TV.
Nunberg spent hours hopping from media outlet to media outlet - an odd strategy, given that one of his arguments for defying the subpoena was that he didn't have the time to search through the emails the grand jury requested.