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."

White House press secretary Jen Psaki was asked during a press briefing Wednesday whether the postponement of Senate hearings for Biden's pick to manage the Office of Management and Budget was a setback and Psaki said she wouldn't "put it in those terms."

Psaki emphasized that the administration is still "fighting" for Tanden's nomination and remains committed to getting Biden's pick confirmed. When asked whether Tanden had offered to withdraw her nomination, Psaki said that is "not the stage" the administration is in.

"The stage we’re in is working to continue to fight for her nomination. And, as you know, it’s a numbers game, right? It's a matter of getting one Republican to support her nomination," Psaki said. "We're continuing to do that outreach, answer questions they have, and continue to reiterate her qualifications."

Rep. Trent Kelly, R-Miss., took to the House floor on Tuesday to speak in favor of his bill to name a Tupelo post office after U.S. Air Force Col. Carlyle “Smitty” Harris, a Vietnam prisoner of war who was held in the infamous "Hanoi Hilton."

The uncontroversial measure was slated to pass under the suspension of the House rules -- with debate expedited because it had the support of two-thirds of the chamber.

But in a surprise move, Rep. Sean Casten, D-Ill., blocked the measure, and instead forced the House to take a recorded vote on the bill Tuesday evening.

The reason? Kelly voted to overturn the election results on Jan. 6.

"As Representatives working every day on behalf of the American people, Rep. Casten believes that working with members regardless of political party is at the core of good public policy," Casten's chief of staff Cara Pavlock said in an email obtained by ABC News. "As a general matter, he does not suggest this action against members with whom we merely disagree, but that willingness to collaborate can only extend so far and to those that also hold the core value of upholding democracy."

"The vote to overturn the election results in the midst of a violent insurrection was a bridge too far," Pavlock wrote, adding that Casten also planned to vote against the post office renaming for that reason.

The bill did pass on a vote of 406-15.

The minor procedural dustup is one of many reminders of how Congress is still grappling with the aftermath of the Jan. 6 Capitol riot and that lawmakers are still coming to terms with how to approach colleagues who supported and amplified former President Donald Trump's efforts to undermine the results of the 2020 election.

-ABC News' Benjamin Siegel