Just 16 days before he's set to leave office, President Donald Trump will headline a rally for Sens. Kelly Loeffler and David Perdue in Dalton, Georgia.

The rally comes on Jan. 4, the night before the two sitting senators face separate Democratic opponents -- Rev. Raphael Warnock and Jon Ossoff, respectively -- in two runoffs that could determine control of the Senate. The makeup of the Senate is currently projected to be 50 Republicans and 48 Democrats and left-leaning independents. If Warnock and Ossoff win, pushing the balance to 50-50, the Democrats would control both the House and Senate, due to Kamala Harris casting the deciding vote in the upper chamber.

Dalton is in Georgia's 14th Congressional District, which makes up the northwest corner of the state and is perhaps the state's most conservative district. Its congresswoman-elect, Marjorie Taylor Greene, has supported QAnon conspiracies in the past and has fully embraced, defended and perpetuated Trump's false narrative about the election.

The 14th Congressional District is also doing the worst of the 14 districts in terms of turnout for the runoff, according to Georgia Votes, which is analyzing the secretary of state's data.

Trump made his one and only appearance in Georgia during the runoff campaign on Dec. 5, when he spent nearly two hours ticking off baseless conspiracies about the presidential election and went on a tangent about how he didn't want to come to appear at the rally.

-ABC News' Quinn Scanlan

Continuing Biden and Vice President-elect Kamala Harris' focus on the worsening coronavirus pandemic Tuesday, the transition team announced nine additional members of the White House COVID-19 response team.

The new members will help focus on the "three crucial aspects of the COVID-19 response strategy: supply chain management, vaccinations, and testing," the transition team said.

"To recover from this pandemic, we must take aggressive action to manufacture, distribute, and administer vaccines, testing, and personal protective equipment in an equitable way. These individuals are deeply qualified and will restore public trust in the pandemic response by leading with facts, science, and integrity,” Biden said in a statement announcing the new members.

-ABC News' Beatrice Peterson

Following a meeting with his COVID-19 task force, Biden delivered remarks on the state of the worsening coronavirus pandemic and slammed the Trump administration for falling behind its goal in distributing vaccines to Americans.

"As I long feared and warned, the effort to distribute and administer the vaccine is not progressing as it should," Biden said. "If it continues to move as it is now, it's going to take years, not months, to vaccinate the American people."

The president-elected noted how officials working on "Operation Warp Speed," the federal government's vaccine program, had predicted this month 20 million vaccinations by the end of the year, but with just a few days left in 2020, the Centers for Disease Control has recorded about 2.1 million Americans as having received a dose.

"This will take more time than anyone would like and more time than the promises from the Trump administration have suggested. This is going to be the greatest operational challenge we've ever faced as a nation," Biden said. "And we're going to get it done."

Biden repeated his intention to invoke the Defense Production Act to compel companies in the private sector to accelerate the production of materials needed for vaccines and testing, as well as protective gear. He also announced that his administration will launch a public education campaign to promote vaccine acceptance and equity.

"We're also going to make sure vaccines are distributed equitably, so every person who wants a vaccine can get it no matter the color of their skin or where they live. We're going to ensure vaccinations are free of charge," he said.

Biden, overall, painted a bleak picture of soaring infections and deaths in the coming weeks, acknowledging the "grim milestone" of the U.S. crossing 330,000 deaths and saying the county may not see improvement until March. He implored Americans to wear a mask and social distance in the meantime -- and called on Trump to set an example.

"It would make a huge difference for President Trump to say 'wear masks.' I hope the President will clearly and unambiguously urge all Americans to take the vaccine once it's available," he said.

After golfing in West Palm Beach, Trump lashed out at Republicans on Twitter Tuesday in response to Senate Majority Leader Mitch McConnell blocking two efforts to pass $2,000 relief checks with a unanimous vote, saying those in his party have a “death wish” for opposing the House-passed measure.

“Unless Republicans have a death wish, and it is also the right thing to do, they must approve the $2000 payments ASAP. $600 IS NOT ENOUGH! Also, get rid of Section 230 - Don’t let Big Tech steal our Country, and don’t let the Democrats steal the Presidential Election. Get tough!” Trump said on Twitter.

It’s unclear at this point how McConnell plans to proceed, but if he does intend to tie those three issues together into one bill, as he suggested he might on the Senate floor earlier Tuesday citing the president's demands, it’s unlikely to pass.

-ABC News' Elizabeth Thomas and Mariam Khan

Russ Vought, the current director of the Office of Management and Budget, struck back at President-elect Joe Biden's transition team one day after it leveled allegations that Trump's OMB was hindering the incoming team.

In a lengthy letter detailing what he says are a number of falsehoods, Vought wrote that Biden's team made false accusations about the OMB and said they fully participated in appropriate transition efforts -- including over 45 meetings.

"As the record shows, OMB has fully participated in appropriate transition efforts," Vought wrote. "What we have not done and will not do is use current OMB staff to write the [Biden transition team]'s legislative policy proposals to dismantle this Administration's work. OMB staff are working on this Administration's policies and will do so until this Administration's final day in office."

"Redirecting staff and resources to draft your team's budget proposals is not an OMB transition responsibility," he added.

In a weekly press conference Wednesday, Biden transition spokesman Yohannes Abraham criticized the Trump administration for failing to cooperate with their agency review teams, particularly with political leaders at OMB.

"In normal transitions -- this was the case in 2008, it was the case in 2016 -- OMB career staff provide critical analytical support to incoming administrations as they look towards the execution of their priorities and the production of their budget," Abraham said. "That analytical support has not been forthcoming from OMB. And there have been no signs that it is -- it will be forthcoming in the days to come."

-ABC News' Elizabeth Thomas and Molly Nagle