Republicans in Texas asked a federal judge on Monday to throw out 127,000 votes in Harris County the day before the election -- in a move Democrats are calling voter suppression.

The votes were cast early via a secure "drive-thru" method that Harris County says it got state approval for back in June amid safety concerns with voting in a pandemic. But Republicans argue the Harris County Clerk was acting on his own by implementing the practice.

A similar lawsuit was rejected by the all-Republican Texas Supreme Court last week and then a second time on Sunday -- a blow to Trump and Republicans who have pushed claims of voter fraud, without evidence, in response to the rulings.

Notably, Texas did not allow for no-excuse absentee voting during the pandemic as other states did, so the drive-thru voting option was developed to ensure at-risk people could vote from the safety of their cars.

At each of the 10 drive-thru centers, voters pulled up in their cars, and after their registrations and identifications were confirmed by poll workers, they were handed an electronic tablet through their car windows to cast ballots.

Harris County, the state's most populous county which leans Democratic, has already set an all-time record for total turnout -- and these drive-thru votes amount for roughly 10% of the total early vote turnout.

-ABC News’ Jon Schlosberg

Making his first campaign stop of the day in Cleveland, Ohio, before barnstorming Pennsylvania, Biden opened his remarks at a drive-in rally by emphasizing to voters there are only hours left until Election Day.

"Tomorrow, we have an opportunity to put an end to a presidency that's divided this nation. Tomorrow, we can put an end to a president that has failed to protect this nation. And tomorrow, we can put an end to a president who has fanned the flames of hate all across this country," Biden began to honking horns of support.

Projecting confidence in the race, Biden said American voters are taking their message -- that “it's time for Donald Trump to pack his bags and go home” -- to the polls in record early voting numbers.

"We're done with the chaos. We're done with the tweets, the anger, the hate, the failure, the irresponsibility," Biden said.

He also drew distinctions on the coronavirus pandemic, slamming Trump for promoting baseless conspiracy theories about doctors tasked with treating COVID-19 and responding to Trump telling his supporters at a Florida rally Sunday night he might wait until after the election when chants of "Fire Fauci" erupted.

"And last night, Trump said he was going to fire Dr. Fauci. Isn’t that wonderful? I got a better idea. Elect me, and I'm gonna hire Dr. Fauci," Biden said. "And we're gonna fire Donald Trump."

Catering his message to farmers in Ohio, Biden called Trump "weak and chaotic” with China on trade, saying farm bankruptcies are up and exports are down. He argued that agricultural exports to China have been 40% lower during the Trump years than they were during the second term of the Obama-Biden administration and went on to pitch the promise of new green energy jobs in Ohio, if he’s elected.

“Ohio, in 2008 and 2012 you placed your trust in me and Barack. In 2020, I am asking you to trust me again," Biden said, painting himself as the unity candidate. “I'm running as a proud Democrat, but I'll govern as an American president. There will be no red states and blue states, just the United States."

Georgia Secretary of State Brad Raffensperger held a news conference this morning from Park Tavern at Piedmont Park in Atlanta -- a polling location that had over 16,000 voters assigned to it during the June primary and some of the longest lines in the county.

Amid lingering accusations of voter suppression in the state, Raffensperger projected confidence in how the fall election has gone so far but also said there will be “challenges” on Tuesday.

"There's never been a perfect election. This one has gone very well so far. Tomorrow we'll have challenges. The job of the counties, the poll managers, the poll workers will be to address those issues quickly. The state stands ready to help, where we can," he said.

Raffensperger said his office has secured nearly 2,000 field service technicians to address issues that may arise at the 2,400 polling precincts statewide.

Providing an update on early voting, Raffensperger said a record 55% of active registered voters have already voted in Georgia and that roughly 1.4 million "would have normally been Election Day voters."

Gabriel Sterling, the statewide voting system implementation manager in Raffensperger’s office, echoed Raffensperger in saying that results in closer races will likely come on Wednesday and added they are expecting legal challenges following the election.

"We anticipate that in any situation where we have a close election like this in what is now viewed as a swing state, there's going to be challenges. There'll be challenges from Republicans. There'll be challenges from Democrats, and we expect them all to be going into court more than likely," Sterling said.

Former President Barack Obama is campaigning for Biden in Georgia Monday as Democrats sense an opportunity to flip the state which Trump won by 5 points in 2016.

-ABC News' Quinn Scanlan

Departing from Delaware to Ohio this morning, Biden signaled a number one to reporters with his finger before audibly saying that there’s "one day" left until the election. He waved and held up one finger again from the top of the staircase before embarking for Cleveland to kick off the final full day of campaigning. 

Moments earlier, Trump in Miami boarded Air Force One, heading off for five rallies across four states including a final rally this evening in Grand Rapids, Michigan, where he closed out his 2016 campaign.

Trump, predicting a "red wave" is relying on his mega-rallies to boost voter turnout and himself to victory as they did in 2016, while Democrats are calling on some star power in the eleventh hour -- recruiting Lady Gaga and John Legend for drive-in rallies in Pennsylvania this evening.

As Trump has threatened legal action to stop the counting of ballots arriving after Election Day, Biden's campaign is making clear that they are "prepared for all scenarios," including the possibility of a post-election legal fight.

In a statement first to Politico confirmed to ABC News, the Biden campaign urged voters to show up in "overwhelming numbers" but also emphasized their large voter protection team and the fact that they are prepared for a potential post-election fight, including making sure they have the resources to fight it.

-ABC News’ Johnny Verhovek contributed to this report.