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

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

Among the the 538 electors who formally cast their votes for president and vice president Monday, there are some notable faces.

In New York, former President Bill Clinton and former Secretary of State Hillary Clinton are among the electors, along with New York Democratic Gov. Andrew Cuomo. 

In Georgia, former Democratic gubernatorial candidate Stacey Abrams is an elector, as is Nikema Williams, the Democratic congresswoman-elect for the district previously represented by late civil rights icon and longtime Rep. John Lewis.

South Dakota GOP Gov. Kristi Noem is an elector in her state, and Chicago's Democratic Mayor Lori Lightfoot already cast her for Biden as an elector for Illinois.

The electors, who reflect the distribution of power across the states based on congressional representation, are decided every four years by each state's political parties in the months before the presidential election. The process for choosing the electors varies by state, with some nominating their electors at party conventions, while others leave it to voters to elect them during the primary process.

-ABC News' Kendall Karson

The Electoral College kicked off voting in four states at 10 a.m. with Indiana, New Hampshire, Tennessee and Vermont being the first states slated to cast electors. While the Electoral College meets on the same day, each state determines when and where its electors meet.

Biden is expected to reach 270 votes -- the number need to win the presidency -- when California's electors vote at 5 p.m.

When will electors vote in the key battlegrounds? 

• *Arizona*: 12 p.m.
• *Georgia:* 12 p.m.
• *Michigan:* 2 p.m.
• *Nevada:* 11:30 a.m.
• *Pennsylvania:* 12 p.m.
• *Wisconsin:* 1 p.m.

Based on the election results, Biden is anticipated to have 306 electoral votes by the end of the day, compared to Trump’s 232.

-ABC News' Kendall Karson