Trump kicked off his rally in Waterford Township, Michigan, by commenting on the cold weather but saying he felt “very warm in this group” before confidently declaring, “Four days from now, we're going to win this state and we're going to go on to win four more great years in the White House.”

An ABC News/Washington Post [poll] () out this week shows Biden narrowly ahead of Trump among likely voters in Michigan, 51% to 44%.

Speaking to the packed crowd of mostly maskless supporters, Trump mocked the size of Biden’s crowds when compared with his, saying “nobody shows up.”

He also took aim at Biden's running mate, and though he regularly mispronounces Kamala Harris’ name, Trump added the false claim that Harris can't pronounce her own name either.

At one point the president called out to Fox News’ Laura Ingraham, who was present and expressed disbelief that she was wearing a mask -- though coronavirus cases are rising in Michigan and nearly every other battleground state.

"Where is Laura? Where is she? I can't recognize you. Is that a mask? No way. Are you wearing a mask? I've never seen her in a mask. Look at you. She's being very politically correct. Whoa!" Trump said.

Ahead of more rallies in Wisconsin and Minnesota, Trump complained that local officials in Minnesota are “scamming” him by not allowing his campaign to hold a rally of more than 250 people in order to adhere to the state's COVID-19 restrictions.

“You know what, that maybe will give us the final victory. We haven't won Minnesota since 1972, OK?" Trump said. "That's not good odds, but we are very popular because I helped with that disaster in Minneapolis."

-ABC News’ Jordyn Phelps

Harris’ first stop in Texas was Fort Worth, where she gave remarks to a socially distanced and masked crowd of about 300 supporters outside of First St. John’s Cathedral -- her presence in the state significant as she’s the first Democrat vice presidential candidate to campaign there since 1988.

After the state shattered its 2016 voting record this morning, Harris praised the more than nine million votes already cast in Texas -- but reminded the race isn’t over yet. 

“Today is the last day of early voting in Texas and you all have been doing your thing! What did I hear? Was it 9 million people have voted so far?" Harris said. "Now, we know this is no time to let up on the pedal though, right?"

Urging Texans to vote whether early or on Election Day, she repeated her mantra that voting is one of the best ways to “honor the ancestors,” paying special tribute to the late Congressman John Lewis. 

“John Lewis lived a life that was about a commitment to fighting for equal rights and civil rights, and it was fight that was born out of being a patriot and loving our country,” she said. “Knowing the best way we achieve our ideals, is to fight for those ideals, to do it in every way by standing up, showing up and speaking up -- so we must vote to honor the ancestors.”

Though winning the state’s 29 electoral college votes is a longshot for the party, some Democrats sense an opportunity to snatch the GOP-stronghold for the first time in more than four decades, while others warn the campaign should stay focused on states Clinton narrowly lost in 2016.

“You are strong, you have power, and at election time, that power will be through your vote. And you will tell them when they ask that you elected Joe Biden the President of the United States,” Harris said closing her remarks. “Thank you Fort Worth, and God bless Texas.”

-ABC News’ Averi Harper

Returning to the state for the first time since campaigning in the Iowa caucuses, Biden made his argument against Trump’s handling of COVID-19 directly to Iowan voters at a drive-in rally this afternoon, emphasizing the jobs lost in Iowa because of, he said, Trump’s unwillingness to deal with the pandemic.

“Eighty-two thousand Iowa jobs lost in the pandemic, and still, they've not come back. Seventy-thousand jobs lost in Iowa since Donald Trump became president. Here at the fairgrounds, the Iowa State Fair cancelled for the first time since World War Two. Donald Trump has given up," Biden said to honking horns of support.

The former vice president repeated his campaign promise that he wouldn’t raise taxes on those making less than $400,000 a year, but said big corporations -- and the president -- will pay their “fair share” in a Biden administration.

"Why should a firefighter, an educator, a nurse, a cop pay at a higher tax rate -- which you do -- than a major multi-billion dollar corporation? Why should you pay more taxes than Donald Trump, who paid $750?" Biden said, referring to a New York Times report. "Well, you ain't going to be gaming the system anymore in a Biden administration. They're going to start paying.”

The race in Iowa is neck and neck with Trump leading by one point according to a Quinnipiac poll published Thursday -- remarkable given that Trump won the state back in 2016 by 10 points. 

While the state only has 6 electoral college votes, it holds a key demographic of Trump's base: farmers. And Biden catered his argument in Des Moines to that key base, arguing he can end trade abuses by China harming their industry, not Trump.

“He [Trump] says, because of, quote, his bailouts, ‘our farmers do better now than when they actually had a farm,’” Biden said. “Look, I'll do what he's been unable to do. I'll mobilize a true international effort to stop China's abuses, so we can strengthen manufacturing and farming in Iowa and across the country.”

In 2016, Trump’s strength in rural counties propelled his victory in Iowa, which saw the largest swing away from Democrats among the six states that flipped from former President Barack Obama to Trump. But Biden also made clear his close relationship to Obama, reminding Iowans they led them to the White House in 2008 and 2012.

"You, too, have a sacred duty -- a duty to vote. It matters," Biden said. "Iowa matters."

-ABC News’ Lauren Lantry contributed to this report.

Wisconsin Department of Health Services told ABC News that a total of five cases have been linked to four different Trump rallies over the last three months.

Here's how the cases breakdown: One case from Oshkosh Trump rally on Aug. 17; One case from Mosinee Trump rally on Sept. 17; Two cases from Janesville Trump rally on Oct. 17; One case from Waukesha Trump rally on Oct. 24

In addition, the health department has identified one case linked to a Biden campaign rally in Manitowoc on Sept. 21.

As ABC News has previously reported, in Minnesota, at least 23 cases have been linked to coronavirus outbreaks from three Trump/Pence campaign rallies in September, and North Carolina on Thursday announced that two people who attended a Trump rally in Gaston County on Oct. 21 have tested positive.

However, Wisconsin Health Services Department cautioned that the above cases from Wisconsin "don't necessarily provide a complete picture."

"Because of the sheer volume they’re working with, our contact tracers are conducting abbreviated versions of full interviews and may not capture all details about where an infection was acquired," Wisconsin health department spokesperson Elizabeth Goodsitt told ABC News. "Also, the people below reported other possible exposures, so we can’t say for sure these events were or were not the cause of these cases."

-ABC News' Soorin Kim