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."

Rep. Ted Budd, R-N.C., had a message for Democrats last summer about their proxy voting system set up during the pandemic: it was an "unconstitutional scheme."

"If you use Nancy Pelosi's proxy to skip work, you shouldn't get paid. It's as simple as that," he said in a June 30 Facebook video introducing his new bill withholding member pay for proxy voting.

Budd wasn't alone: A handful of House Republicans previously critical of the proxy vote system submitted letters to have colleagues vote for them, while they were scheduled to appear at CPAC.

Freshman Rep. Madison Cawthorn, R-N.C., tweeted last summer that leaders "show up no matter how uncertain the times are," and that Democrats were "cowards for hiding" and proxy voting.

He was also in Orlando on Friday, telling conservatives activists, "If we sit on the sidelines, we will not have a country to inherit."

"If we do not get involved and say that it is our duty to make sure that our country is responsible, that our country doesn't take away our liberties, then my friends, we will lose this nation," Cawthorn said.

Others Republicans scheduled to appear at CPAC on Friday who also planned to vote by proxy included Reps. Greg Steube of Florida, Virginia Foxx of North Carolina, and Matt Gaetz of Florida, who was one of the first Republicans to support proxy voting.

Curtis Kalin, a spokesman for Budd, said the congressman still opposes proxy voting, and will donate his salary for the days he used the system to a restaurant relief fund, given his bill last year, "The No Pay for Proxy Voting Act."

The Republicans who attended CPAC aren't alone in their questionable use of the proxy voting system -- established by House Speaker Nancy Pelosi, D-Calif., last year to cut down member travel to Washington during the COVID-19 pandemic.

Last year, Rep. Greg Stanton, D-Ariz., was caught voting during a Transportation Committee hearing from a boat during a family trip to Utah. Stanton later apologized and said he "messed up." And several House Democrats voted by proxy last May in order to attend a SpaceX rocket launch in Florida.-ABC News' Benjamin Siegel