Transcript for Race for president becomes sprint to the finish
We begin tonight with America's race for president, now a sprint to the finish. 16 days until election day. President trump and Joe Biden trading blows on the campaign trail today. Both locked in on battleground states. The president in Nevada, after holding rallies in Wisconsin and Michigan. Facing backlash for attacking governor Gretchen Whitmer just days after she was targeted in an alleged terror plot. Joe Biden hitting North Carolina today. Saying president trump continues to lie about the coronavirus. Biden downplaying his lead in the polls. Urging supporters not to get complacent. Early voting under way in record numbers. Thousands casting their ballots at Boston's Fenway park this weekend. More than 26 million voting nationwide so far. Rachel Scott leads us off. Reporter: Tonight, with just 16 days to go until election day, Joe Biden urging his supporters to get their ballots in now. Don't wait. Go vote today. Reporter: Over 26 million Americans have already voted with record-shattering turnout across the country. Lines wrapping around Boston's Fenway park. I just voted. Whoo-hoo! Reporter: And voters waiting in line for hours in the battleground state of North Carolina. We gotta keep the incredible momentum going. We can't let up. Reporter: In our latest national poll, Biden is up by 12 points, the same margin by which Hillary Clinton led in 2016 at this point in October. The Biden campaign, fearing a repeat of four years ago, blasting out this memo warning, "Donald Trump can still win this race," and, "We need to campaign like we're trailing." President trump spending most of his time campaigning hard in states he won in 2016, trying to fire up his base. Usa! Usa! If I lose, can you imagine? If I lose, I will have lost to the worst candidate -- the worst candidate in the history of presidential politics. Reporter: But the president's rhetoric isn't doing much to expand his support. The crowd chanting "Lock her up" at this Michigan rally as the president criticized the state's governor Gretchen Whitmer. You have got to get your governor to open up your state. Okay? The schools have to be open, right? Lock them up! Lock them up! Lock them all up. Reporter: Whitmer saying the president's words are putting her life in danger. Just days ago, the FBI foiled an alleged plot to kidnap her, saying the suspects charged were angry over her lockdown restrictions. It's incredibly disturbing that the president of the united States, ten days after a plot to kidnap, put me on trial, and execute me, the president is at it again and inspiring and incentivizing and inciting this kind of domestic terrorism. Reporter: Members of the president's own party are now breaking ranks. Nebraska senator Ben sasse, facing his own re-election challenge, warning losing the white house could bring the Republican senate down too. I'm now looking at the possibility of a Republican bloodbath in the senate. And that's why I've never been on the trump train. Reporter: The president calling sasse a "Liability to the Republican party and an embarrassment." And the chairwoman of the RNC sending this message to Republicans now publicly distancing themselves. Any Republican that doesn't recognize that running with the president is going to help them is hurting themselves in the long run. Rachel, there are some cracks in Republican support for the president, we just heard it right there. Criticism growing in some GOP circles. But the president will keep his foot on the gas, blitzing several battleground states? Reporter: He's keeping a packed schedule. Tonight in Nevada. But he's spending time in north Carolina and Pennsylvania. States he won in 2016. This is a campaign that has long had goals of expanding the map, trying to flip the states the president lost. But in the final days of this campaign, the president is on defense. Tom? Rachel, thank you. Tonight's other major headline, the coronavirus surging across the U.S.
This transcript has been automatically generated and may not be 100% accurate.