Opening the night's discussion on the economy, Harris said firmly that Biden would repeal Trump's 2017 tax cuts "on day one."

"He'll get rid of it," she said. "And what he'll do with the money is invest it in the American people and through a plan that is about investing in infrastructure, something that Donald Trump said he would do, I remember hearing about some infrastructure week, I don't think it ever happened."

"But Joe Biden will do that. He'll invest in infrastructure. It's about upgrading our roads and bridges but also investing in clean energy and renewable energy," she added.

Pence responded by attacking the state of the economy after the Obama administration and tried to tie Biden and Harris to the Green New Deal proposal.

"When President Trump and I took office, America had gone through the slowest economic recovery since the Great Depression," he said. "Because when Joe Biden was president, they tried to tax and spend and regulate and bail our way back to a growing economy."

When Harris responded again during the open discussion section, she underscored that her and Biden's plan would only raise taxes on wealthy Americans.

"We saw enough of it in last week's debate, but I think this is supposed to be a debate based on fact and truth," she said.  "And the truth and the fact is, Joe Biden has been very clear, he will not raise taxes on anybody who makes less than $400,000."

Pence argued that the Trump tax plan lowered taxes for average Americans and that a repeal would mean higher taxes for everyone, not just the wealthy.

"It would be important if you said the truth. Joe Biden said twice in the debate last week that he's going to repeal the Trump tax cuts," he said. "That was tax cuts that gave the average working family $2,000 in a tax break every single year."

Page pivoted the conversation to climate change, noting the U.S. has seen record-setting hurricanes in the South and record-setting wildfires in the West this year, setting the stakes and posing the first question to the vice president.

"Do you believe, as the scientific community has concluded, that man-made climate change has made wildfires hotter and more deadly and hurricanes wetter and more damaging?" Page asked.

Pence didn't directly answer but warned Harris would sign the U.S. back into the Paris Climate Accord and falsely claimed Biden and Harris have committed to abolishing fossil fuel and banning fracking.

"President Trump and I believe that the progress that we have made in a cleaner environment has been happening precisely because we have a strong free market economy," Pence said.

Harris, once a proponent of the Green New Deal as both a co-sponsor of Sen. Bernie Sanders' bill and as a presidential candidate -- is now embracing Biden's climate plan and defended her running mate's record.

"First of all, I will repeat, and the American people know, that Joe Biden will not ban fracking. That is a fact. That is a fact," Harris began. "We have seen a pattern with this administration, which is, they don't believe in science."

"Joe sees what's happening on the Gulf states, which are being battered by storms. Joe has seen and talked with the farmers in Iowa whose entire crops have been destroyed because of floods. And so Joe believes, again, in science," Harris said, adding that a Biden-Harris administration would "re-enter the climate agreement with pride."

Page then asked if Pence agrees with Harris that climate change poses an existential threat to humans.

"As I said, Susan, the climate is changing. We'll follow the science," Pence said, before launching into an attack on Biden's tax plan.

Continuing on the theme of transparency, Page asked Harris, "Do voters have a right to know more detailed health information about presidential candidates especially when they're facing a challenge?"

Harris said "absolutely" and raised recent reporting on Trump's taxes.

"That's why Joe Biden has been so incredibly transparent, and certainly by contrast, the president has not. Both in terms of health records, but also let's look at taxes. We now know because of great investigative journalism that Donald Trump paid $750 in taxes. When I first heard about it, I literally said, 'You mean $750,000?'" Harris said. "And it was like, 'No, $750.'"

"We now know Donald Trump owes and is in debt for $400 million," she said, in reference to New York Times reporting. "It would be really good to know who the president of the United States, the commander in chief, owes money to because the American people have a right to know what is influencing the president's decisions and is he making those decisions on the best interest of the American people, of you, or self-interest?"

Pence defended the attack by painting Trump as a "businessman" and "job creator."

"He's paid tens of millions of dollars in taxes, payroll taxes, property taxes. He's created tens of thousands of American jobs. The president said those public reports are not accurate and the president's also released literally stacks of financial disclosures the American people can review just as the law allows," Pence said, though Trump has not released his tax returns, repeatedly saying they're under audit.

When asked about whether Harris had spoken with Biden about a plan in case of presidential disability, she touted her career and the historic nature of her nomination, but she said their shared purpose is the reason she is on the ticket with Biden.

"I think Joe has asked me to serve with him because he knows that we share, we share a purpose which is about lifting up the American people," Harris said. "And after the four years that we have seen of Donald Trump, unifying our country around our common values and principles."

In response to the same question, Pence touted the "transparency" that the White House practiced while the president was hospitalized at Walter Reed Medical Center.

"The American people have a right to know about the health and well-being of their president and we'll continue to do that," Pence said.

Pence has stood by and pushed the Trump campaign message of "law and order" and has remained a vigorous defender of police. In an interview with ABC News Live Anchor Linsey Davis, Pence said that he and Trump "reject the notion from Joe Biden and others that there's an 'implicit bias' towards minorities in law enforcement."

"The president and I know we don't have to choose between supporting law enforcement and supporting all of the families that live in our major cities," Pence told a crowd of supporters in Lititz, Pennsylvania. "We have done both for the last three and a half years, and we're going to support law enforcement and support our African American and minority families for four more years in the White House."

The vice president has dismissed the "defund the police" movement and has called for more resources and better training and accountability in law enforcement.

On matters of racial discrimination in policing and use of force, Harris has called for the rooting out of racial discrimination. In the aftermath of George Floyd's killing while in police custody she participated in protests in Washington, D.C.

During an appearance on ABC's "The View" in June, Harris was asked by co-host Meghan McCain if she supports the "Defund the Police" slogan, but did not give a direct answer on where she stands.

"We need to re-imagine how we are achieving public safety in America. And to have cities where one-third of their entire budget is going to policing but yet there's a dire need in those same cities for mental health resources, for resources going into public schools, for resources going into job training and job creation. Come on. We have to be honest about this that there isn't a consensus around this because if there were, we would actually see a smarter distribution of resources in our country to address the issues that need to be addressed."

After the shooting by police of Jacob Blake, she met with Blake's family in Wisconsin and spoke with Blake over the phone. She also told NBC News, "I think that there should be a thorough investigation, and based on what I've seen, it seems that the officer should be charged." She's also kept in contact with Tamika Palmer, the mother of Breonna Taylor who was shot by Louisvill, Kentucky, police while she was sleeping in her home.

Harris has called for economic and educational investment in communities of color to create safer, healthier communities. She and Biden have called for an end to no-knock warrants, chokeholds and carotid holds. They want to create a national excessive force standard and create a database to track cops who use excessive force and break the rules. The pair want to end cash bail and private prisons.

"We have to understand that you can't think that the only way to create safe communities is to put more police on the streets, that's not how it's going to work," Harris told pop star Lizzo on an Instagram Live stream in September.

In contrast, Harris wrote in her 2009 book "Smart on Crime," "if we take a show of hands of those who would like to see more police officers on the street, mine would shoot up."

-ABC News' Justin Gomez and Averi Harper