Hours after President Donald Trump fired acting Attorney General Sally Yates for refusing to back his executive order restricting immigration, her newly installed replacement ordered Department of Justice staffers to "defend the lawful orders of our president."
Yates defended her decision in a tweet posted from on her personal Twitter account Tuesday. "I took and upheld oath to defend the constitution no to someone's personal likings," she tweeted.
Trump appointed Dana Boente to serve as acting attorney general until the Senate confirms a full-time choice. The Senate Judiciary Committee is expected to vote Tuesday on the nomination of Senator Jeff Sessions, and approval from the full Senate could come later this week.
The drama that unfolded Monday began with Yates, who was appointed by former President Barack Obama, issuing written guidance to DOJ employees saying she was not convinced that a defense of Trump's executive order was lawful.
"My responsibility is to ensure that the position of the Department of Justice is not only legally defensible, but is informed by our best view of what the law is after consideration of all the facts," Yates said. "In addition, I am responsible for ensuring that the positions we take in court remain consistent with this institution's solemn obligation to always seek justice and stand for what is right."
The White House sharply criticized Yates in a statement announcing her firing, saying she "betrayed the Department of Justice by refusing to enforce a legal order designed to protect the citizens of the United States."
The statement from the press secretary's office said Trump's order was approved "as to form and legality" by the DOJ's Office of Legal Counsel.
Yates, in her directive, said that type of review does not take into account statements made by administration officials that may be relevant to an order's purpose, or whether the policy is "wise or just."
The executive order, signed last week, suspends U.S. entry to all refugees for 120 days and bans Syrian refugees indefinitely. It also blocks people from Iraq, Iran, Libya, Syria, Sudan, Yemen and Somalia from entering the U.S. for three months.
The White House further defended the order Monday, saying that seeking "tougher vetting for individuals traveling form seven dangerous places is not extreme."
House speaker Paul Ryan also defended Trump's order Tuesday, saying "the president has a responsibility to the security of this country." He did say that "regrettably the rollout was confusing."
WATCH: Ryan on immigration order
Trump proposed about a year ago a ban on all Muslims entering the U.S., which he later amended to calling for "extreme vetting" of people from countries with links to terrorism.
The president's decision to fire Yates drew objections from many Democrats in Congress, including House Democratic Whip Steny Hoyer, who called the move "alarming."
"The American people need to consider whether President Trump simply plans to dismiss anyone with whom he disagrees, and I hope my Republican colleagues stand up and express concern over this as well," Hoyer said.
Senator Chuck Schumer, who described the immigration ban as "un-American," wrote on Twitter: "The AG should pledge fidelity to the law and the Constitution not the White House. The fact that this [administration] doesn't understand that is chilling."
One of Trump's opponents in the race for the Republican nomination during the presidential race, Senator Ted Cruz, strongly defended the decision to fire Yates, describing her actions as a "fitting and sad" last act of Obama's DOJ.
"President Trump was exactly right to fire an acting attorney general who refused to carry out her constitutional duty to enforce and defend the law," Cruz said.
Senator Dick Durbin, who is on the committee voting on the Sessions nomination, said if Trump's reaction to Yates is how he deals with dissent, "it's a dangerous path for America."
Sessions was himself a member of the Senate Judiciary Committee in 2015 when Yates went through the confirmation process to become the deputy attorney general in Obama's administration.
During the hearing, he asked Yates, "If the views the president wants to execute are unlawful, should the attorney general or the deputy attorney general say no?"
Yates replied, "Senator, I believe that the attorney general or the deputy attorney general has an obligation to follow the law and the Constitution, and to give their independent legal advice to the president."
The opposition to Trump's executive order is also coming from former officials, including a group of more than 130 who served under Obama and former President George W. Bush. They sent a letter Monday to the heads of the Justice Department, State Department and Department of Homeland Security expressing "deep concern" over the order that they say "will do long-term damage to our national security."
The letter says counterterrorism partners in Europe are distancing themselves from the U.S., undoing years of effort to bring them closer.
"Moreover, because the order discriminates against Muslim travelers and immigrants, it has already sent exactly the wrong message to the Muslim community here at home and all over the world: that the U.S. government is at war with them based on their religion."
Demonstrators block an escalator at the international terminal in protest of President Donald Trump's executive order banning travel from seven Muslim-majority countries at San Francisco International Airport, Jan. 29, 2017.
The former officials welcomed the clarification that permanent residents would not be banned from entering the U.S., but urged the departments to work to allow "other classes of people into the country."
Those signing the letter included former Secretary of State Madeleine Albright, former DHS Secretary Janet Napolitano, former National Security Advisor Susan Rice and former CIA chief Michael Hayden.