Some lawyers not involved in the case expressed surprise that, given the potential legal pitfalls of the criminal investigation, Kushner or any other Trump advisers would take the risk of talking to Congress, given that such statements could be used against them later by criminal prosecutors.
"It's a very difficult tightrope to walk,'' said Justin Dillon, a former federal prosecutor now in private practice. "He has to balance the political fallout from taking the Fifth Amendment with the potential criminal fallout of talking.''
Dillon predicted anything Kushner tells the committee will be shared with Mueller.
The Kushner interview also comes after the president and his legal team have discussed his power to pardon those close to him and even himself. After a Washington Post report on those conversations, the President tweeted this weekend that he has "complete power to pardon''.
Dillon said the possibility of a future pardon could affect Kushner's overall legal strategy.
"No one who has paid any attention to this administration should doubt that if Kushner ever needs a pardon, he will get one,'' he said.
Through lawyers and his spokesman, Kushner has long insisted he did nothing wrong. Kushner lawyer Abbe Lowell has said his client "is prepared to voluntarily cooperate and provide whatever information he has on the investigations to Congress''. He said Kushner "appreciates the opportunity to assist in putting this matter to rest''.
Kushner is expected to answer the committee's questions and not invoke his Fifth Amendment right against self-incrimination, according to a person familiar with Kushner's thinking.
Kushner is not expected to be under oath during his questioning tomorrow - but that arrangement still poses significant legal risks to someone under investigation.
Kushner is likely to face extensive questions about meetings he attended with Russian government officials or people connected to the Russian Government.
In June 2016, he attended a meeting at Trump Tower in New York arranged by his brother-in-law, Donald Trump jnr, on the premise that a lawyer had damaging information about Democratic presidential candidate Hillary Clinton. That meeting is also being investigated by the FBI and Mueller.
No one who has paid any attention to this administration should doubt that if Kushner ever needs a pardon, he will get one
Investigators have also been interested in meetings Kushner had in December - after Trump's election but before he was sworn in as president. That month, he met Russian Ambassador Sergey Kislyak, and then later met Sergey Gorkov, head of Vnesheconbank, which has been under US sanctions since 2014.
The bank has said the session was to talk to Kushner about his family's real estate business. The White House has said the meeting was unrelated to business and was part of Kushner's busy diplomatic schedule.
Kushner's meetings with foreigners, and Russians in particular, have become a sticking point for his security clearance process.
Three times since January, Kushner has filed updates to his national security questionnaire, to add previously undisclosed meetings with foreign officials. Such mistakes can have significant legal and career consequences for government employees, because it is a crime to submit false information on such forms.
One update added more than 100 calls or meetings with representatives of more than 20 countries, most of which came during the presidential transition, according to one of Kushner's lawyers, who have said he did nothing wrong and his meetings simply reflect his role as Trump's principle adviser on foreign policy issues.
