VALDOSTA, Ga. – Hours before the polls open in Georgia and 10 other states, the Republican frontrunner made a final pitch to voters Valdosta, Georgia.

A large crowd gathered for a rally Monday evening at the athletic complex at Valdosta State University. The building seats more than 5,000 but has more room on the floor and elsewhere. There was standing room only at the event.

During the rally, Trump's campaign announced the following endorsements: NASCAR CEO Brian France, retired driver Bill Elliott and active drivers Chase Elliott, Ryan Newman and David Lee Regan.

“I am proud to receive the endorsement of such an iconic brand and a quality person such as Brian," said Trump. "Brian has a wonderful family and is an incredibly successful business person. I have great respect for Brian and I am grateful for his support and that of Bill Elliott, one of the best drivers in history, and active stock car racers, including his son Chase Elliott, Ryan Newman and David Lee Regan.”

France said Trump is changing American politics forever and his leadership and strength are desperately needed.

"He has had an incredible career and achieved tremendous success. This is what we need for our country,” said France.

Trump is the first presidential candidate in the south Georgia town since Ronald Reagan visited in 1980.

The crowd was filled with supporters like small business owner Brad Mathis. "We're hoping Donald Trump gets in there, we're here to support him. We're very interested and curious about what he has to say," said Mathis.

Kent Justice spoke with a first-time voter named Amanda following the event. She said, "As a Republican, voting tomorrow for the first time, I was actually very interested in what Mr. Trump had to say. Originally I came to see the 'spectacle,' yet I actually agreed with many of his points. His businessman personality and confidence really do help his claims. He is someone I will keep in mind when I cast my vote tomorrow," Amanda said.

Trump's appearance comes as a sharp new divide erupted between Republicans who pledge to fall in line behind Trump if he wins their party's nomination and others who insist they can never back the bombastic billionaire.

The fissure could have major implications beyond the primaries, exposing the looming challenges in uniting the party after the election, no matter who wins.



Nebraska's Ben Sasse, a rising star among conservatives, became the first current senator to publicly raise the prospect of backing a third party option if Trump clinches the nomination. In a letter posted on Facebook late Sunday, Sasse urged Republicans to consider whether a party led by Trump would still represent their interests.



"If our party is no longer working for the things we believe in - like defending the sanctity of life, stopping Obamacare, protecting the Second Amendment, etc. - then people of good conscience should stop supporting that party until it is reformed," he wrote.



Other Republican leaders were less explicit, but sent similar messages on Monday, particularly in light of Trump's refusal to immediately disavow former Ku Klux Klan leader David Duke's support.



Mitt Romney, the party's 2012 nominee, called that "disqualifying." And South Carolina Gov. Nikki Haley, campaigning in Atlanta alongside Florida Sen. Marco Rubio, said she would "not stop fighting a man who refuses to disavow the KKK."



Trump said he had not understood the interviewer who first raised the question about Duke, and he did later repudiate him. "How many times do I have to continue to disavow people?" he said.



Several high-profile Republicans and conservative writers have embraced an anti-Trump social media campaign, using the Twitter hashtag "NeverTrump."



Trump has won three of four early primary contests, roiling a party that had assumed his populist appeal with voters would fizzle. Instead, he's only grown stronger and appears to be in commanding position heading into Super Tuesday, the biggest single-day delegate haul of the year.



The Associated Press asked Republican senators and governors across the country if they would back Trump if he secured the nomination. Just under half of those who responded would not commit to backing him, foreshadowing a potentially extraordinary break this fall.



"I am increasingly concerned by Donald Trump's statements and behavior, and I have serious concerns about his ability to win the general election and provide presidential leadership," Indiana Sen. Dan Coats said in a statement to AP.



Tensions boiled over during Trump's rally Monday in Radford, Virginia, where he was repeatedly disrupted by demonstrators, including 20 or more chanting "Black lives matter." At another point, he asked a protester, "Are you from Mexico?" after he was interrupted during remarks about immigration. He ordered several people to be removed, then cast himself as a unifying political force.



"Believe it or not, we're going to unify this country," he said.



If Trump sweeps most of the states up for grabs Tuesday, he could amass a delegate lead that would be difficult for any rival to overcome. Texas Sen. Ted Cruz is banking on a win in his home state to keep him in the race, while Rubio wants to stay close in the delegate count until the primary hits his home state of Florida on March 15.



Meanwhile, Democratic front-runner Hillary Clinton is solidifying her lead. Like Trump, Clinton could begin putting her party's nomination out of reach for rival Bernie Sanders with a strong showing on Super Tuesday.



As Trump has rolled through the early voting states, he's received enthusiastic endorsements from New Jersey Gov. Chris Christie and from Alabama Sen. Jeff Sessions, one of the most vocal opponents of immigration -law changes on Capitol Hill. Several other party officials have said they would back the real estate mogul if he does become the nominee, though some say their support would be reluctant.



"I'm a Republican and I will support the nominee," Alabama Gov. Robert Bentley said Monday. "I do not think he is our best nominee, but I will support the nominee."



Party leaders are particularly worried about the ripple effect of a Trump nomination on other races. Arkansas Gov. Asa Hutchinson urged Republicans to remember that their White House pick also impacts "the Senate and whether we're going to continue to elect Republican governors across the country."



A new commercial released Monday by Arizona Rep. Ann Kirkpatrick, who is challenging John McCain for his Senate seat, served as a likely preview of how Democrats would seek to link GOP candidates to Trump. The 60-second spot highlighted several of Trump's more incendiary statements and questioned how McCain could say he would support him in the general election.



Some Republicans said Senate candidates and others would have to forgo party unity in order to save themselves.



"It's not going to be a team effort. It's going to be every man for himself," said Matt Mackowiak, a GOP strategist who is unaffiliated in the 2016 race.



