Trump-Biden transition updates: Trump continues to tout he won election at Ga. rally

Georgia Gov. Brian Kemp responded Saturday to a tweet from Trump earlier in the day saying he will "easily & quickly win Georgia" if Kemp and the secretary of state "permit a simple signature verification."

"As I told the President this morning, I’ve publicly called for a signature audit three times (11/20, 11/24, 12/3) to restore confidence in our election process and to ensure that only legal votes are counted in Georgia," Kemp tweeted, just hours ahead of Trump's rally in the Peach State.

Trump has used his bully pulpit to slam Kemp, a longtime Trump supporter, as he has refused to echo the president’s baseless allegations of fraud in Georgia.

The president has tweeted that Kemp was "hapless" and should "overrule his obstinate secretary of state," Brad Raffensperger -- also a Republican backer of Trump -- after the latter refused to intervene to help Trump.

"The governor's done nothing," Trump said during a Fox News interview. "He's done absolutely nothing. I'm ashamed that I endorsed him."

The Twitter exchange comes as Trump is set to speak at a rally for Republican Senate candidates in the state -- races that will determine the balance of the Senate.

On Friday, Kemp was expected to meet Vice President Mike Pence, also in the state for a rally, on the tarmac upon his arrival in Savannah, but he could not due to a family emergency.

Kemp is not attending Trump’s rally Saturday, according to his Communications Director Cody Hall.

-ABC News' Elizabeth Thomas, Jordyn Phelps, Ben Gittleson, Olivia Rubin, Will Steakin, Quinn Scanlan, Rachel Scott and Matthew Mosk

White House coronavirus response coordinator Deborah Birx said on Friday that her role in the Biden administration remains unclear.

“I don’t know what my role will be come Jan. 20,” Birx told Rhode Island station WPRI.

Earlier this week, Biden's team had made contact with both Birx and National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci, holding separate meetings with the two White House coronavirus task force officials.

"I was privileged to brief them on Monday," Birx said in a separate interview Friday with ABC Des Moines affiliate WOI. "I will tell you they had very good questions, very well informed questions and as a civil servant, I always stand ready to serve any administration."

ABC News reported in November that Birx expressed a desire to continue serving in a Biden administration, according to colleagues.

However, Birx has found herself in an increasingly complicated position as she combats the virus while serving a president who has ignored science and downplayed the pandemic.

Her rosy presentations from the White House podium and presence alongside Trump at news conferences this spring -- as well as her attempt to explain away Trump's suggestion in April that Americans could inject disinfectant to treat the virus -- have hurt her credibility and led to charges she has enabled the president.

-ABC News' Ahmad Hemingway and Ben Gittleson

As President Donald Trump and his allies continue their legal barrage in an effort to overturn the presidential election despite a succession of adverse rulings, some state and local election officials are starting to cry foul.

In Michigan Thursday, Republican lawyers were back in court seeking an audit of election results in the heavily-Democratic county that is home to Detroit -- even after the state's Supreme Court had already rejected an earlier request from the same group to halt certification. An exasperated lawyer for the city pleaded with the judge to do something.

"They are trying to use this court in a very, very improper way," said Detroit city attorney David Fink. "We ask this court not just to deny the relief that is requested but to grant significant sanctions, because this has to stop."

The attorney for the Trump poll observers shot back: "I didn't realize I was such a threat to our republic by simply asking that this court to enforce our constitutional right."

The Michigan case is not isolated, and opponents say they are starting to see the relentless effort as abusive. In just the past week, at least five new cases were filed on the president's behalf. Between the Trump campaign and the president's allies, there have now been at least 46 lawsuits filed challenging the 2020 presidential contest -- many employing the same recycled fraud claims and witness affidavits.

And if more cases land on court dockets with glaring errors or what judges have described as anemic evidence, legal experts told ABC News that even some slow-to-boil judges may see no choice but to impose sanctions.

"You could see a court saying, 'Enough is enough,'" said Daniel I. Weiner, deputy director of the Brennan Center for Justice's Election Reform Program at New York University.

-ABC News' Olivia Rubin, Matthew Mosk, Luke Barr, Ali Dukakis

Trump and his allies lost three more cases in their effort to litigate his defeat to Biden by more than 6 million votes. Judges in Georgia, Michigan and Nevada continued to show little patience for the president's effort.

The 11th Circuit Court of Appeals on Friday dismissed an appeal from former Trump lawyer Sidney Powell seeking an investigation of Dominion machines and sent the case back down to the lower court to be litigated there, saying it does not have jurisdiction to hear the case.

The lower court's ruling in the case-- which is seeking to reverse President Trump's loss in the state-- had actually given Powell a partial win and ordered the state to freeze the machines while the case was heard. Powell appealed anyway -- a move the judges found objectionable.

A Michigan Court of Appeals on Friday also denied the Trump campaign's request to appeal a defeat in a lower court in a 2-1 decision, saying the issue is now moot. The suit, which sought to halt the counting of ballots in the state, had been rejected by a lower court nearly a month ago and sat untouched on appeal for over three weeks -- rejected by a judge as "defective" and only corrected by the campaign just a few days ago.

Another GOP attempt to overturn the 2020 election failed Friday in Nevada, where Carson City District Court Judge James T. Russell dismissed a case and prevented the GOP from bringing it back before the court. At issue were Nevada’s signature matching machines, which the GOP Plaintiffs alleged had failed to match mail-in ballot signatures closely enough to those on file, potentially accepting fraudulent votes.

One judge in Nevada called the GOP expert testimony  "of little to no value” and said the pro-Trump legal team "failed to meet their burden to provide credible and relevant evidence... to contest the November 3, 10 2020 General Election."

-ABC News' Matthew Mosk