The Justice Department issued its 14-page opinion on Friday, according to the Justice Department’s Office of Legal Council.

The office said that a federal anti-nepotism law passed in 1967 “does not bar this appointment because of the President’s special hiring authority.” This opinion is based on a law passed in 1978 which gives the president the authority to appoint White House officials, overriding the nepotism law.

The opinion was written by Deputy Assistant Attorney General Daniel Koffsky.

The anti-nepotism law reportedly was put in place since after President John F. Kennedy named his brother, Robert, attorney general, in order to prevent a president from nominating or appointing close family, including in-laws, to administration positions.

Kushner, an Orthodox Jew who married Trump’s eldest daughter, Ivanka,  was named by the president a senior White House adviser, his transition team announced earlier this month. Kushner, a wealthy businessman and real estate developer, served as a top confidante to Trump during the campaign. He reportedly will not take money for his work.

It is possible for Kushner’s appointment to be challenged in court, though it would have to be by someone who can show they were harmed by the appointment, according to Politico. The Justice Department’s opinion does not have standing in court.

Trump said in recent interviews that Kushner would work to broker peace between Israel and the Palestinians, and expressed confidence that he would be successful.

Trump’s endorsement of Kushner for Middle East peace negotiator follows a series of statements in which Trump expressed confidence in Kushner’s abilities in that capacity.

“Jared is such a good kid and he’ll make a deal with Israel that no one else can — you know he’s a natural, he’s a great deal, he’s a natural — you know what I was talking about, natural — he’s a natural deal-maker — everyone likes him,” Trump said in an interview earlier this month in The Times of London and Bild.

Kushner and Ivanka Trump reportedly will be moving to a home in Washington, D.C., in the tony Kalorama neighborhood.