Biden will nominate Rep. Marcia Fudge, D-Ohio, to lead the Department of Housing and Urban Development, sources familiar with the president-elect's decision told ABC News.

Fudge, who had campaigned openly to become the first Black secretary of agriculture, would be the second member of the Congressional Black Caucus to join the Biden administration, following Rep. Cedric Richmond, D-La., a key Biden surrogate who will serve as a senior White House official.

She would be Biden's third African-American cabinet nominee, after Linda Thomas-Greenfield, his pick to serve as U.S. ambassador to the United Nations, and retired Army Gen. Lloyd Austin, who he said Tuesday would be his nominee to lead the Pentagon.

The move would put Fudge at the helm of the $50 billion department as the country faces a potential housing crisis in the new year -- with many Americans struggling to pay rent, and others worried they will not be able to do so in the next few months as the economy continues to languish due to the coronavirus pandemic.

Approached by reporters on Capitol Hill Tuesday, Fudge said she hadn't been formally offered the job by Biden, but said the two had spoken previously.

"If I were to be named, certainly it's an honor and a privilege to be asked to be in a president's Cabinet," she said. "If I can help this president in any way possible, I am more than happy to do it."

Fudge, a member of the House Agriculture Committee and Committee on Education and Labor, represents the Cleveland area, as well as Akron, Ohio.

When she was openly campaigning for the nomination to lead the department of agriculture, she lamented the possibility of leading HUD.

"As this country becomes more and more diverse, we're going to have to stop looking at only certain agencies as those that people like me fit in. You know, it's always 'we want to put the Black person in labor or HUD,'" she told Politico last month.

Fudge's move to the Biden administration would further tighten House Speaker Nancy Pelosi's fragile majority, making it even harder for Democrats to pass any legislation until Fudge's replacement is seated later next year.

"I'm in a safe district," Fudge told reporters. "We're just hopeful that if this works out the way we'd like it to, that it will be OK."

-ABC News' Benjamin Siegel, Katherine Faulders, Beatrice Peterson and John Verhovek

In a single, succinct order, the U.S. Supreme Court has shut down an 11th-hour attempt by allies of Trump in Pennsylvania to block its slate of certified electors and toss out 2.5 million mail-in ballots.

"The application for injunctive relief presented to Justice Alito and by him referred to the Court is denied," the court said.

The appeal -- brought by U.S. Rep. Mike Kelly, a Pennsylvania Republican, along with another GOP candidate for Congress -- alleged that the state legislature did not legally pass the law allowing for expanded mail-in voting during the pandemic. They sought the justices to order all mail-in ballots thrown out along with the state's official certification of election results, which was signed by Gov. Tom Wolf last week.

The Supreme Court's denial comes on the same day the state of Texas filed suit against four battleground states alleging that they "exploited the COVID-19 pandemic" to improperly loosen election rules and skew the contest's outcome. Justices have not yet said whether they will hear the case.

The actions come on the Dec. 8 "safe harbor" deadline by which states must lock in the slate of electors they intend to send to Congress to affirm the election results -- selections that are intended to match the will of the voters.

-ABC News' Devin Dwyer, Alex Hosenball, Olivia Rubin and Matthew Mosk

Shortly before releasing his press release confirming retired four-star Gen. Lloyd Austin as his pick to lead the Pentagon, The Atlantic magazine published an op-ed penned by Biden op-ed, laying out the reasons behind his choice and noting their history together in the Obama administration.

“Today, I ask Lloyd Austin to once more take on a mission for the United States of America—this time as the secretary-designate of the Department of Defense. I know he will do an outstanding job,” Biden wrote.

Austin, the former commander of U.S. Central Command -- with jurisdiction over military activities in the Middle East -- retired in 2016 after more than 40 years of military service. If confirmed, he would be the first African American to lead the Pentagon.

Biden pointed to Austin’s ”many strengths and his intimate knowledge of the Department of Defense and our government” as factors that made him “the person we need in this moment," saying his experience leading the Iraq drawdown prepares him for coordinating vaccine distribution and connecting with American families.

“And the next secretary of defense will have to make sure that our armed forces reflect and promote the full diversity of our nation. Austin will bring to the job not only his personal experience, but the stories of the countless young people he has mentored. If confirmed, he will ensure that every member of the armed forces is treated with dignity and respect, including Black, Latino, Asian American, Native American, women, and LGBTQ service members," Biden wrote.

Biden also seemed to address the fact that Lloyd’s nomination would require a waiver given his recent military service -- something that some Democrats have already expressed opposition to.

“I respect and believe in the importance of civilian control of our military and in the importance of a strong civil-military working relationship at DoD—as does Austin," he wrote.

"Austin also knows that the secretary of defense has a different set of responsibilities than a general officer and that the civil-military dynamic has been under great stress these past four years," Biden added.

The announcement comes as Biden and Vice President-elect Kamala Harris meet with civil rights leaders who have pushed Biden to name more people of color to senior-level Cabinet positions.

-ABC News' Molly Nagle

Trump this afternoon kicked off a self-congratulatory vaccine "summit" to tout the speed at which COVID-19 vaccines were produced -- speaking at the same time Biden was introducing his key health appointments and nominees.

The room in the Eisenhower Executive Office Building on the White House complex was packed for the three-hour event, and it appeared almost everyone was wearing a mask, save for Trump.

Asked why no members of the Biden transition were invited to participate, the president falsely claimed he won the election and that he won key swing states where Biden actually was victorious.

“We’re gonna have to see who the next administration is because we won in those swing states -- and there was terrible things that went on. So we’re gonna have to see who the next administration is,” Trump said. “But whichever the next administration is will really benefit by what we’ve been able to do with this incredible science.”

“We were rewarded with a victory,” Trump continued. “Let's see whether or not somebody has the courage -- whether it's legislatures or a justice of the Supreme Court or a number of justice of the Supreme Court. Let's see if they have the courage to do what everybody in this country knows is right.”

To date, Trump, his campaign and its allies have seen at least 38 defeats in court.

-ABC News' Ben Gittleson and Jordyn Phelps

With just hours to go until Tuesday's "safe harbor" federal law-mandated deadline for states to certify their election results and next Monday's Electoral College voting coming up, time is running out for Trump to find a way to overturn the results of the presidential election as he’s set out to do.

The president held a rally in Georgia -- his first since losing the election -- to campaign for the upcoming Senate runoffs there, races which will determine whether the GOP maintains control, but instead he spent most of his 101 minutes on stage pushing a whirlwind of unsubstantiated claims that the election was stolen.

Trump directly called on GOP Gov. Brian Kemp to "immediately ask for a special session of the legislature" -- which could theoretically set up the process of allowing lawmakers to appoint new electors who would support Trump over Biden despite Biden winning by nearly 12,000 votes in the state.

But Georgia officials have rejected Trump's call.

Kemp, joined by GOP Lt. Gov. Geoff Duncan, said in a statement late Sunday it would be unconstitutional for the legislature to "retroactively change" the process for choosing presidential electors, saying "doing this in order to select a separate slate of presidential electors is not an option that is allowed under state or federal law."

While Kemp and Duncan, along with GOP Secretary of State Brad Raffensperger and officials in his office, have said the only option in disputing the results is through the courts, pro-Trump efforts have ended in at least 38 defeats to date, with only a single court victory -- in a case in Pennsylvania that was ultimately not consequential.

It all comes as the president’s personal attorney tasked with leading his efforts to overturn the election in court, Rudy Giuliani, who has been traveling the country as part of the president's ongoing efforts to dispute election results, remains hospitalized with COVID-19 at MedStar Georgetown University Hospital in Washington since Sunday. The Arizona legislature has closed for the week "out of an abundance of caution" after Giuliani met with roughly a dozen GOP lawmakers.

As deadlines loom, Trump on Monday presents the presidential Medal of Freedom to wrestling legend Dan Gable at noon and meets with Vice President Mike Pence behind closed doors.

And while Trump administration officials vow that with vaccine on the horizon, life will soon return to normal, the Biden team is sounding alarms on its distribution, saying they still don’t have access to the plan to roll it out.

"We have yet to see any kind of detailed plan," Dr. Celine Gounder, an expert on Biden’s COVID-19 advisory board, told "CBS This Morning" Monday after Biden said the same last week.

Pressing forward with the transition despite Trump's roadblocks, Biden and Vice President-elect Harris will receive the President’s Daily Brief and meet with transition advisors on Monday ahead of personally debuting their new health picks, who will inherit leading the country through the ongoing coronavirus pandemic.