Trump-Biden transition: Attorney Sidney Powell back at White House

With the president and his allies continuing their pressure campaign to overturn the election, some of the battleground states where Biden won are taking additional security precautions to safeguard their electors meeting Monday.

In Georgia, a spokesperson for Van R. Johnson, the mayor of Savannah and an elector for Biden this year, confirmed that he has additional security measures in place today as a "precautionary measure," without providing details on any specifics. The measures were first reported by the New York Times.

The Democratic Party of Georgia would only say that they've taken "every measure" to ensure the safety of their electors. 

In Michigan, where protests are planned outside the state Capitol, electors were promised police escorts, ABC News confirmed. 

Late Sunday night, officials announced that the state legislature's office buildings will be closed to the public due to "credible threats of violence." The decision to close the state House and Senate offices while the presidential electors convene to cast their votes for Biden came from a recommendation from law enforcement. It was not motivated by anticipated protests outside the capitol, according to a statement from Amber McCann, a spokesperson for Senate Majority Leader Mike Shirkey. 

In Arizona, the secretary of state’s office is not publicizing the location of their meeting due to “security reasons,” according to a spokesperson. 

-ABC News' Kendall Karson, Alisa Wiersema, Quinn Scanlan and Meg Cunningham

The normally conservative-leaning Wisconsin Supreme Court has ruled 4-3 against President Trump, rejecting his effort to challenge the state’s election recount, saying he tried to throw the challenge flag "long after the last play, or even the last game."

"The challenge … is meritless on its face," wrote Justice Brian Hagedorn, who spent years as the chief counsel to Republican Gov. Scott Walker, in the majority opinion.

The court’s majority takes issue with a number of the complaints leveled by the Trump campaign about how mail-in ballots were collected. But the four justices ultimately agreed that any issues should have been raised well before the election, not after the president lost.

"The issues raised in this case, had they been pressed earlier, could have been resolved long before the election," Hagedorn wrote. "The Campaign's delay in raising these issues was unreasonable in the extreme."

Chief Justice Patience Drake Roggensack authored the dissent, which argued that the court’s majority hid behind the argument that Trump’s filing came too late, in order not to address concerns the president raised about the way ballots were collected. Roggensack said there were “numerous problems that will be repeated again and again, until this court has the courage to correct them.”

Biden won Wisconsin by more than 20,000 votes.

-ABC News' Matthew Mosk, Alex Hosenball and Soo Rin Kim

In a video meeting with little fanfare, Nevada's six Democratic electors cast votes for Biden and Vice President-elect Kamala Harris -- the first electors in the country to cast their votes. Silent clapping ensued at the conclusion of the meeting.

Prior to the electors casting their votes for Biden and Harris, deputy Secretary of State Mark Wlaschin reminded the electors they are legally required to vote for the Democratic ticket as it clinched more votes in the state, and if they did not, they would be replaced. At the start of the meeting, they signed a pledge agreeing to vote for the candidates who received the highest number of votes in the general election.

"In addition to this pledge, state law requires you to vote for Joseph R. Biden for president, and Kamala D. Harris for vice president. If you vote for any other person, or leave your ballot blank, neither of your ballots will be accepted, and your position as Presidential Elector will be vacated, and an alternate would be selected to fill your vacancy," Wlaschin said.

Thirty-three states -- including Nevada -- and Washington, D.C., require electors to keep their pledge. In at least five states, penalties exist for defiant votes, while over a dozen states cancel and replace the rogue elector. 

More laws are likely to be enacted over the coming years to require electors to follow the popular vote after the U.S. Supreme Court ruled earlier in the year that it is constitutionally permissible to bind electors to vote for the popular vote winner. 

While experts aren't anticipating any spectacles with "faithless" electors this year, ten members of the Electoral College voted or attempted to vote against the candidate that won in their state in 2016. 

-ABC News' Kendall Karson

An alternate Republican elector must now cast votes for Trump and Vice President Mike Pence in Florida after state Sen. Wilton Simpson, the newly elected Senate president, tested positive for coronavirus and is no longer able to attend the ceremony. 

Katie Betta, a spokesperson for Simpson, confirmed that the senator took a test Sunday night that came back positive. Better said Simpson tests regularly because he travels often, both for his work with the Senate and his personal business. She said that he is experiencing "some very mild symptoms," which she said the senator “compared ... to the symptoms he's had before with allergies or like a very mild head cold."

ABC News has asked the Republican Party of Florida who the alternate will be ahead of the electors meeting at 2 p.m.

-ABC News' Kendall Karson