After an expanded detention facility for child migrants reopened in Carrizo Springs, Texas, Rep. Alexandria Ocasio-Cortez, D-N.Y., tweeted Tuesday, “This is not okay, never has been okay, never will be okay - no matter the administration or party.”

In a press briefing Wednesday, Psaki attempted to cast the Biden administration’s efforts to manage immigration as a major improvement over President Donald Trump’s policies but didn’t fully address Ocasio-Cortez's criticism that such facilities shouldn’t exist at all.

Psaki said the administration had three options when it comes to child migrants: to send them back to their countries (which she said can be dangerous), to transfer them to a facility managed by the Department of Health and Human Services, or to put them in the care of families or sponsors "without any vetting." She said the administration has chosen the middle option.

“What we are doing is working as quickly as possible to process these kids into these HHS facilities, which have been revamped, which have medical and educational services available, so that we can then transfer them to families. That's what our approach is,” Psaki said.

Psaki would not commit to a request to allow media in to prove that children are treated humanely, citing privacy and security concerns. Psaki tried to explain the administration’s options in dealing with minors at the border and why the detention facilities have become a primary strategy.

“This is a difficult situation. It's a difficult choice. That's the choice we've made,” she said.

Psaki also attempted to defend delays in transferring children from facilities run by Customs and Border Protection, which often lack amenities, to Health and Human Service facilities that are intended for longer-term care. By law, children are supposed to spend no more than 72 hours in Customs and Border Protection facilities after initial apprehension.

“There were some delays last week because of weather, and because some of these facilities to safely move these kids to, did not have power and were not in a place where they could -- they had the capacity to take in these kids and do it safely. That is not our objective. That is not our goal," Psaki said. "So some, unfortunately, did stay four days, five days, or longer, but the objective is to move them as quickly as possible to the HHS sponsored facilities.”

-ABC News' Sarah Kolinovsky

In keeping with the White House's focus of the day, Biden held a bipartisan Oval Office meeting Wednesday with House and Senate members ahead of signing an executive order mandating a review of critical U.S. supply chains.

"The last year has shown the vulnerability we have with some of the supply chains, including the PPE that we needed badly but had to go abroad to get. And there are current strategies," Biden said.

Biden praised the bipartisan effort to address the shortage of the chips for cars and said the group planned to discuss the problem, along with other shortage issues.

-ABC News' Molly Nagle

The White House was surprised to discover that Johnson & Johnson will only have about 3 to 4 million doses of its vaccine ready to ship once the FDA grants an emergency use authorization, White House press secretary Jen Psaki said during a press briefing Wednesday.

Johnson & Johnson had estimated it could ship 12 million doses at the end of February in a $1 billion contract signed with the federal government in August.

“We were surprised to learn that Johnson & Johnson was behind on their manufacturing. As you noted, it was kind of reported earlier to be about 10 million, and now it's more like 3 to 4 million doses that they would be ready to ship next week if they are moved through the FDA process, which is not yet concluded, just to note," Psaki said. "And we are going to continue to work with them on ensuring that that can be expedited.”

Despite the initial availability, Johnson & Johnson has said it expects 20 million doses to be available by the end of March and to meet its contractual obligation for 100 million doses by the end of June.

-ABC News' Sarah Kolinovsky

Veteran diplomat Linda Thomas-Greenfield was sworn in Wednesday morning as Biden's U.N. ambassador. Thomas-Greenfield, known for her "gumbo diplomacy", is a Louisiana native and child of the segregated South.

After being sworn in, Thomas-Greenfield tweeted saying she was "honored" to hold the post.

"Diplomacy is back. Multilateralism is back," Thomas-Greenfield said in the tweet. "America is back."

Garland described the Jan. 6 insurrection at the Capitol as "the most heinous attack on the democratic processes I have ever seen and one I never expected to see in my lifetime." He added he will make sure to provide career prosecutors all the resources they need to carry out their investigations while also taking a broader look at the symptoms behind the country's domestic extremism problem.

Asked by Sen. Dianne Feinstein, D-Calif., whether the president "has the absolute right to do what he wants with the Justice Department," Garland said presidents are "constrained by the Constitution as are all government officials" and cited comments by Biden committing to not interfere with Justice Department matters. At the same time, Garland said that the Department of Justice is part of the executive branch and because of that, on policy matters they do "follow the lead of the president and the administration as long as it is consistent with the law." When asked who an attorney general represents when his interests conflict with the president's, Garland said the attorney general "represents the public interest, particularly and specifically as defined by the Constitution and the statutes of the United States."

Asked whether the president can order an attorney general to open or close an investigation, Garland said such a question was a hard one for constitutional law but that he did not expect it to be a question for himself given President Biden's statements assuring independence for the department.

Sen. Lindsey Graham, R-S.C., took a contentious tone with Garland in his line of questioning as he pressed him on multiple topics. At one point, when Graham asked Garland whether he thought former FBI Director Comey was a good FBI director, Garland declined to answer, which Graham said he found "stunning" because he thought Comey was terrible. Sen. Sheldon Whitehouse, D-R.I., pressed Garland on whether he would commit to investigating not only the rioters who attacked the Capitol on Jan. 6, but those "upstream" like the funders, organizers, ringleaders or others not actually at the Capitol.  Garland cited his past experience as a line prosecutor, noting "we begin with the people on the ground and we work our way up to those who are involved and further involved -- and we will pursue these leads wherever they take us."

Asked about whether he would end the Trump Justice Department's policy of generally stonewalling in the face of oversight requests from Congress, Garland committed to Whitehouse that the department would be "as responsive as possible" to any requests and "at the very least why if it can't answer a question or can't answer a letter." Garland also committed that he would work with Whitehouse on getting answers to the committee on requests that the Justice Department under Attorneys General Bill Barr and Jeff Sessions previously ignored.

In an exchange with Sen. John Cornyn, R-Texas, Garland committed that his personal politics will have no impact on prosecutions and investigations he oversees as attorney general. Asked what he would do if he was ordered to do something that he considered to be unlawful, Garland said he would first tell the president or whoever else was asking him that what they were ordering was unlawful and would resign if no alternative was accepted.

Asked by Sen. Amy Klobuchar, D-Minn., what he will do to improve morale in the department, Garland said he would on his first day make an oath to career prosecutors and agents "that my job is to protect them from partisan or other improper motives." Klobuchar then asked Garland whether he believes he'd need "additional authorities" to combat the country's domestic terrorism problem. Garland said while the department "is probably always looking for new tools ... the first thing we have to do is figure out whether the tools that we have are sufficient."

-ABC News' Alexander Mallin