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.