The US Department of Justice won't defend President Donald Trump's heavy restrictions on travel including banning people from seven Muslim-majority countries.
Acting Attorney-General Sally Yates, a Democratic nominee, has ordered no evidence be presented in those cases, saying in a letter to Department of Justice lawyers she's not convinced Mr Trump's executive order is actually lawful.
The decree from the 45th President puts in place a 90-day visa suspension for anyone arriving from Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen.
It also suspends the entry of refugees into the US for four months and imposes an indefinite ban on Syrian refugees.
A cap of 50,000 refugees to be accepted in 2017 was also introduced - less than half of the 110,000 former President Barack Obama had set.
Over the weekend in which Mr Trump signed off on the executive order, his administration says just 109 people of 325,000 who entered the US over 24 hours were questioned by officials.
All of them were eventually let in.
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But the move was still met with protests in the US and abroad, with many taking to John F Kennedy International Airport and other international airports with placards and signs, urging those affected to be let in.
A number of legal challenges have been issued in a number of jurisdictions; the Department of Justice's position on those cases is Ms Yates' "ultimate responsibility".
Ms Yates' letter is another apparent blow to Mr Trump's ambitions.
"At present, I am not convinced that the defense of the Executive Order is consistent with these responsibilities nor am I convinced the Executive Order is lawful.
"Consequently, for as long as I am the Acting Attorney General, the Department of Justice will not present arguments in defense of the Executive Order, unless and until I become convinced that it is appropriate to do so," the one-page letter reads.
Alongside the massive protests, major American corporations such as Starbucks, Google, Facebook, Twitter and Microsoft have also taken a stand against the ban.