Biden signed an executive order Wednesday that will begin a 100-day investigation into vulnerabilities in the supply chain of critical sectors including computer chips, large capacity batteries, active pharmaceutical ingredients and critical and strategic materials, including rare earth minerals.

Biden touted the move as something that will strengthen America for future challenges like the COVID-19 pandemic, which revealed myriad flaws in the supply chain.

"This is about making sure the United States can meet every challenge we face in this new era," Biden said. "Pandemics, but also in defense, cybersecurity, climate change, and so much more. And the best way to do that is by protecting and sharpening America’s competitive edge by investing here at home."

In remarks before the signing, he called the subject one of few "where Republicans and Democrats agreed," having met earlier in the day with a bipartisan group of lawmakers.

Sen. Richard Shelby, R-Ala., a top Republican on the Appropriations Committee, is throwing his weight behind an alternative nominee to head the Office of Management and Budget: Shalanda Young.

Young was nominated by Biden to be deputy director of the Office of Management and Budget. Young was most recently the staff director at House Appropriations, and she and Shelby have a close working relationship.

“I believe she would be good in that role. She’s smart, she knows the process inside-out, and she’s an honest broker who has demonstrated the ability to work with both sides and get things done. She would have my support, and I suspect many of my Republican colleagues would support her, as well," Shelby said in a statement. "But that’s up to the Biden Administration.”

White House press secretary Jen Psaki was asked about Shelby's support on Wednesday and the possibility of Young being a Neera Tanden replacement, but she made clear that the White House maintains support for Tanden.

-ABC News' Trish Turner

Energy and Natural Resources Committee Chairman Sen. Joe Manchin, D-W.V., will vote to confirm Rep. Deb Haaland's, D-Ariz., nomination to serve as secretary of the interior, easing concerns that Haaland's appointment could be in jeopardy.

Manchin has been in close focus on this and other nominations this week, as the moderate Democrat has significant ability to jeopardize nominees in the evenly divided Senate.

Manchin has said he will oppose the nomination of Neera Tanden to the Office of Management and Budget and has not committed to a position on Xavier Becerra's nomination to lead the Department of Health and Human Services.

"I believe that every Presidential nominee and every Member of Congress must be committed to a new era of bipartisanship. That is the standard the overwhelming majority of Americans expect and deserve," Manchin said in a statement. "With respect to Representative Haaland and her confirmation hearing, while we do not agree on every issue, she reaffirmed her strong commitment to bipartisanship, addressing the diverse needs of our country and maintaining our nation’s energy independence."

-ABC News' Allison Pecorin

Biden has officially extended the national emergency declared over the COVID-19 pandemic beyond March 1. By law, the national emergency would have ended a year after it was declared unless the president took action within 90 days of the expiration date.

"The COVID-19 pandemic continues to cause significant risk to the public health and safety of the Nation," Biden wrote in his letter to Congress. "More than 500,000 people in this Nation have perished from the disease, and it is essential to continue to combat and respond to COVID-19 with the full capacity and capability of the Federal Government."

The national emergency was initially ordered by former President Donald Trump on March 13, 2020, freeing up financial resources for the country as the pandemic took hold.

-ABC News' Molly Nagle

On the second day of Judge Merrick Garland's confirmation hearing, the nominee will not testify but five witnesses will testify virtually about his nomination and credentials. Those witnesses include Wade Henderson, CEO of the Leadership Conference on Civil and Human Rights, Josh Blackman, South College Texas of law professor, Andrea Tucker, a mother in D.C., whose twin children Garland tutors, Ken Starr, former solicitor general and U.S. circuit judge, and Donna Bucella, former director for Executive Office of U.S. attorneys.

Garland emerged virtually unscathed after Monday's hearing, earning praise from senators on both sides of the aisle as he fielded questions on domestic terrorism, racial justice issues and restoring independence to the Justice Department, among other topics.

Republican Sens. Ted Cruz, R-Texas, and Tom Cotton, R-Ark., did express concern over what they described as Garland's unwillingness to pledge that he will not fire special counsel John Durham without proper cause, a commitment they note former attorney general William Barr made during his confirmation hearing about then-special counsel Robert Mueller.

Garland repeatedly emphasized that because he had no knowledge of Durham's investigation he wanted to meet with him first before making a decision but said that because Durham hasn't yet been fired in the new administration he sees no reason to doubt that decision.

Other Republicans, like Sen. Josh Hawley, R-Mo., appeared to grow frustrated over Garland's unwillingness to engage on questions about his views on immigration policy. Garland said he was not completely aware of Biden's immigration policy proposals so declined to wade into the issue.

-ABC News' Alexander Mallin