Just hours before she was sacked, Sally Yates had told lawyers at the Department of Justice NOT to defend the executive order in court.
She was appointed by President Obama, but has been replaced by Dana Boente who's reversed her order.
The White House has accused Ms Yates of betrayal.
Dana Boente, U.S. Attorney for the Eastern District of Virginia has been sworn in as acting U.S. attorney general until Donald Trump's nominee Jeff Sessions is approved.
Boente said in an interview with the Washington Post that he would enforce the immigration order.
Here at home
This morning's cabinet meeting's expected to be dominated by Donald Trump's immigration controls.
Independent ministers are furious at the actions of the US President.
Taoiseach Enda Kenny's refusing to cancel his St. Patrick's Day trip to the White House but has ordered a complete review of US pre-clearance at Irish airports.
There's been global outcry at Donald Trump's 90 day hold on citizens from seven Muslim countries.
The independent alliance say they're incensed at it and Ministers Shane Ross and Finian McGrath will raise it at Cabinet this morning.
And Minister Katherine Zappone called for a review of US pre-clearance at Irish airports after one person was refused it at Dublin.
Last night the Taoiseach ordered a complete review of the system at Dublin and Shannon.
Enda Kenny also declared he disagrees with the policy introduced by Donald Trump and says he will tell him that when he visits in March.
And that's a clear message to the calls from the opposition and doubts within the government about the visit to the White House in March – the Taoiseach says he doesn't want to abandon the influence and become isolationist by not going.
Image: Saul Loeb. AFP. Getty Images
