On the eve of Election Day, former President Donald Trump teased Monday night that he will make a "very big announcement" on Nov. 15 at his Mar-a-Lago estate in Palm Beach, Florida.

Trump was speaking at a final rally in Dayton, Ohio, for Republican Senate candidate J.D. Vance and others.

While the former president did not specify the nature of the upcoming announcement, sources told ABC News last week that he could announce a 2024 presidential run as early as next week -- though the sources cautioned that discussions about the specifics, including a date, were still fluid.

“We want nothing to distract from the importance of tomorrow,” Trump said at the rally.

-- ABC News' Teddy Grant and Paulina Tam

Biden made one last campaign pitch to voters Monday night from a rally at Bowie State University in Maryland. This cycle, he warned, will shape "what the next couple of decades look like."

"Let's be clear, this election isn't a referendum, it's a choice," he said at the event in support of Democratic gubernatorial candidate Wes Moore. "It's a choice between two very different visions of America.”

Biden listed legislative accomplishments from Democrats during his first two years -- including low unemployment, job creation, infrastructure investments and more -- before turning to criticism of "MAGA Republicans."

"The hypocrisy is unbelievable," he said, slamming GOP lawmakers who oppose student loan relief despite receiving business loans and debt cancellation during the coronavirus pandemic, or who touted aspects of the American Rescue Plan despite not voting in favor of the bill.

Biden also called out election deniers within the Republican Party, saying they only see two outcomes: “Either they win, or they were cheated.”

"Today, we face an inflection point," Biden said as he closed his remarks. "One of those moments that comes around every three or four generations. We know in our bones that our democracy is at risk, and we know that this is your moment to defend it, preserve and protect it, choose it. We'll meet this moment."

Voters who were never mailed their absentee ballot in Cobb County, Georgia, will still be able to vote, according to a new court ruling.

Approximately 1,036 voters in the county had requested a ballot but never received them. Ballots are supposed to be mailed within three days after election officials receive ballot requests. However, election workers in the county failed to upload absentee voting information to a ballot mailing system on Oct. 13 and Oct. 22.

Now, the Cobb County Board of Elections will send ballots to those voters Monday by overnight delivery, according to the court ruling. Those voters can mail their ballots provided they are postmarked by 7 p.m. on Nov. 8 and returned by Nov. 14. Email and text updates will be provided to those affected voters so they are able to track their ballot.

Voters affected by the error will also be able to vote in person Tuesday or by a federal write-in absentee ballot.

One of the main criticisms from Democrats regarding SB 202 -- the sweeping elections bill signed by Gov. Brian Kemp last year -- has been focused on mail-in ballots. Previously, voters were able to request absentee ballots 180 days before an election and the county could start mailing them out 49 days before Election Day. Now, voters can only request ballots within 78 days of an election and they can't be mailed until 29 days before.

-ABC News' Lalee Ibssa

President Joe Biden said Monday he thinks Democrats will “surprise the living devil out of a lot of people" in the midterm elections.

“Imagine what we can do in a second term if we maintain control,” Biden said during a virtual Democratic reception.

“I know that sounds like a very high expectation,” Biden said, adding, “I’m optimistic.”

At a second Democratic reception Monday, the president said, “We’re going up against some of the darkest forces we’ve ever seen in our history. These MAGA Republicans are a different breed … this is not your father’s Republican Party. It’s a different deal."

Biden added, “We have a shot at keeping the Senate, increase in it, and I am optimistic about the House, as well.”

-ABC News’ Jordyn Phelps