Republicans continued to question Barrett on her impartiality, with Sen. Ben Sasse of Nebraska asking Barrett to confirm that judges can make decisions without imposing their own views.

"I hope that's what people think because that's what I have always driven to do. In my time as a judge, my job, my boss is the rule of law, not imposing my policy preferences," Barrett said.

Barrett was then asked to explain why judges wear black robes in our judicial system, in another opportunity to emphasize her commitment to the law, not her personal views in a courtroom.

"Chief Justice John Marshall started the practice in the beginning. Justices used to wear colorful robes that identified them with the schools they graduated from. John Marshall decided to wear a simple black robe. Pretty soon the other justices followed suit and now all judges do it," Barrett said, before offering her take on the garb.

“I think the black robe shows that justice is blind. We all dress the same. It shows once we put it on, we are standing united symbolically, speaking in the name of the law, not speaking for ourselves as individuals," she said.

Demonstrators protested the Senate Judiciary Committee hearing outside the Supreme Court Tuesday. One group wore masks and waved signs that featured Justice Ruth Bader Ginsburg's "dissenting collar."

Outside the Senate office building where Barrett's confirmation hearing was taking place, some of her supporters were praying.

Under questioning from Sen. Klobuchar, Barrett said Roe v. Wade is not a "super-precedent" -- so it could theoretically be overturned by the Supreme Court.

Earlier, Barrett said that Brown v. Board of Education, which established that racial segregation in schools is unconstitutional, is one of just a handful of cases she and some others consider to be "super-precedent" or settled law.

“Is Roe a super-precedent?” Klobuchar asked, before Barrett asked in return, “How would you define ‘super-precedent?’”

“I'm asking you,” Klobuchar said.

“People use super-precedent differently. The way that I was using it in the article that you’re reading was to define cases that are so well-settled that no political actors ... seriously push for their overruling. I'm answering a lot of questions about Roe v. Wade which I think indicates Roe v. Wade doesn't fall in that category. Descriptively means it's a case, not a case that everyone has accepted,” Barrett said.

Sen. Amy Klobuchar, D-Minn., used the metaphor of "following the tracks" to suggest how Barrett would likely vote on landmark cases involving health care, abortion and voting rights, using Barrett’s past writings and the words of President Trump.

"I think the American people have to understand that you would be the polar opposite of Justice Ginsburg," Klobuchar said. "She and Justice Scalia were friends, yes, but she never embraced his legal philosophy. So that's what concerns me."

Klobuchar pressed Barrett on voting rights, raising Barrett’s dissent in the Kanter v. Barr case Sen. Durbin raised earlier, in which Barrett suggested the Constitution protects the right of non-violent felons to own guns but does not protect their right to vote -- a right she wrote belongs "only to virtuous citizens."

"How do you define the word virtuous?" Klobuchar questioned. "It doesn't appear in the Constitution… We are living in a time or a lot of people are having their voting rights taken away from them. What's virtuous?

"Senator, I want to be clear that that is not in the opinion designed to denigrate the right to vote which is fundamental. The distinction between civic and individual rights is one that is present in the court decisions and it has to do with the jurisprudential view," Barrett said, saying it was a common, long-standing judicial term of art, not a character judgment. "It doesn't mean, I think, anybody gets a measure of virtue and whether they are good or not and whether they are allowed to vote. That's not what I said."

Barrett dodged several questions on election-related questions, citing the "Ginsburg rule."

"Do you think a reasonable person would feel intimidated by the presence of armed civilian groups at the polls?" she asked.

"Senator Klobuchar, you know that is eliciting. I'm not sure it's eliciting a legal opinion for me because a reasonable person standard, as you know, is more common in the law. Or just an opinion as a citizen. It's not something really that's appropriate for me to comment on," Barrett replied.

The Democratic nominee for vice president, Sen. Kamala Harris, D-Calif., appearing virtually, opened her line of questioning with a 10-minute defense of the Affordable Care Act, arguing Republicans are confirming Barrett before the election so they can achieve their goal of getting the court to strike down the health care law.

She asked Barrett when she wrote the article which criticized the majority decision of Chief Justice Roberts to uphold the Affordable Care Act, homing in on the timeline.

Barrett said she didn’t remember when she wrote it, but Harris responded that Trump nominated Barrett to the Seventh Circuit court five months after the article was published.

"In other words, the Affordable Care Act and its protections hinge on this seat,” Harris claimed. "You've already opined the constitutionality of the Affordable Care Act. And that position satisfied the president's promise to only nominate judges who would tear down the Affordable Care Act."

Harris also asked if she was aware of Trump's statements committing to nominate judges who would strike down the Affordable Care Act before she was picked -- to which Barrett said she didn’t recall.

"I want to be very very careful. I'm under oath. As I'm sitting here, I don't recall seeing those statements,” Barrett said.

Highlighting the real-world impact of the health care law, as her Democratic colleagues had before her, Harris then asked, “Would you consider the 135 million people who gained protection under the Affordable Care Act when deciding the case that challenges that law?"

"Senator Harris, if I were to be confirmed and conclude that I was not -- I was able to sit on the case pursuant to the recusal statute and heard the case and decided the case, I would consider all the protections that Congress put in place," Barrett said.

Harris ended her questioning by arguing Barrett has been much less forthcoming than Justice Ginsburg was in her confirmation hearing, specifically when it came to legislation involving reproductive rights, but said the American people should be familiar with Barrett's views by now.

“I would suggest that we not pretend that we don't know how this nominee views a woman's right to choose," she added, referring to Roe v. Wade.