Pennsylvania Secretary of State Al Schmidt projected confidence about the security of the election, saying it will be "free, fair, safe and secure," during brief remarks Monday.

Schmidt warned Pennsylvania voters to "remain vigilant" about any last-minute misinformation and disinformation that may try to persuade them not to vote.

Schmidt also seemed to try to set expectations for the timing of results in the key battleground state, reminding people that Pennsylvania has "never" had final official results on election night regardless of when the media have called the state.

"We can't predict what percentage of those votes will be counted on election night," Schmidt said.

He noted that 2 million mail-in ballots have been returned so far, which officials can't begin opening until Tuesday morning.

"That means election officials can't even remove the ballot from their envelope," Schmidt underscored.

He said counties will begin to submit unofficial election results beginning at 8 p.m. ET -- and will continue updating throughout the night and "in the subsequent days."

-ABC News' Olivia Rubin

The Republican National Committee filed a lawsuit against the Milwaukee Election Commission on Monday, accusing the city agency of "arbitrarily limiting observers" at polling places.

The RNC alleged that the Milwaukee Election Commission limited the number of observers at some early voting sites to only one observer per political party, in violation of state law. During the early voting period, access was limited at three polling locations, according to the lawsuit.

"Interest in this election is at unprecedented levels in American history, as that has generated corresponding interest in observing the voting process in the City of Milwaukee," the lawsuit said.

According to the lawsuit, the Milwaukee Election Commission plans to continue limiting the total number of observers on Election Day depending on the "space, access, number of voters, and other prevailing circumstances" at polling locations.

The RNC is asking the court to order the Milwaukee Election Commission "to allow the public to observe all public aspects of the voting process."

Representatives for the Milwaukee Election Commission could not be immediately reached for comment.

In September, the RNC filed a lawsuit against the city of Racine, Wisconsin for not hiring enough Republican election inspectors for this summer’s primary election.

-ABC News' Kelsey Walsh and Peter Charalambous

Former President Donald Trump kicked off his final day on the campaign trail Monday at a poorly attended rally in North Carolina, where the venue was at least a third empty.

Sparsely populated to begin with, dozens of people left the venue in a steady stream throughout the rambling, unfocused speech.

At one point, Trump told North Carolinians who are desperately waiting for help after hurricane devastation to "sit back and relax" until he takes office.

"Those people, they better get that FEMA here fast. But we're going to on Jan. 20," Trump said. "Just tell everybody to sit back, relax. On Jan. 20, you'll see people come in and help you out like we did in the past."

-ABC News' Soo Rin Kim, Lalee Ibssa and Kelsey Walsh

During his two-hour testimony at an ongoing hearing over Elon Musk and his super PAC's $1 million voter sweepstakes, Philadelphia District Attorney Larry Krasner characterized America PAC's admission that winners are preselected as the "most amazingly disingenuous defense I have ever heard."

"This was all political marketing masquerading as a lottery," Krasner said during the hearing in the Philadelphia County Court of Common Pleas. "This has been a grift from the beginning. This has been a scam from the very beginning."

According to Chris Gober, a lawyer for Musk and America PAC, the winners were selected based on their "suitability" as spokespeople, signed a contract and received the million dollars as a "salary" for their work, despite Musk himself publicly saying that winners would be selected "randomly."

Krasner’s attorney, John Summers, described the claim as "a flat-out admission of liability." While America PAC has openly acknowledged that winners would serve as spokespeople, the hearing marks the first time they have disclosed that the winners were preselected.

"It is deceptive. It is misleading. It is taking advantage of people,” Krasner said. "They are doing everything under the sun to cover it up."

Musk's lawyers have repeatedly argued that the case itself is politically motivated, accusing Krasner of creating a "political circus." Krasner’s attorney attempted to counter that argument by mentioning that Krasner drives a Tesla -- made by the electric car company owned by Musk -- and would theoretically bring the same case against Taylor Swift if she arranged a similar scheme for Harris.

"I have brought action against Democrats in the past," Krasner said. "I would have brought an action against Taylor Swift if she did this. As far as I know, she didn't."

The court is currently on a lunch break following testimony from Krasner, who was the hearing's first witness.

-ABC News' Peter Charalambous