Here are highlights of how both sides set the stage for questioning.
The high-stakes confirmation hearing for Judge Amy Coney Barrett, President Donald Trump’s Supreme Court nominee, got underway Monday as Senate Republicans push for a final vote before Election Day despite Democratic calls to let voters decide who should pick a new justice.
Trump nominated Barrett to fill the seat left by the late Justice Ruth Bader Ginsburg.
The four days of Senate Judiciary Committee hearings, overseen by chairman Sen. Lindsey Graham, are unprecedented, with some members participating virtually and in-person. Barrett will appear at the witness table to face questions each day.
Hearings start at 9 a.m. each day and will be live streamed on ABC News Live.
Barrett, 48, a devout Roman Catholic, was a law clerk to conservative Justice Antonin Scalia, considers him her mentor and follows his originalist interpretation of the Constitution. She practiced law at a Washington firm for two years before returning to her alma mater, Notre Dame Law School, to teach. She was nominated by Trump to the Seventh U.S. Circuit Court of Appeals in May 2017 and confirmed by the Senate that October in a 55-43 vote.
Judge Amy Coney Barrett has arrived to testify before the Senate Judiciary Committee on the first day of her Supreme Court confirmation hearing.
The hearings are expected to last a few days as Barrett will face questions from both Republican and Democratic senators on the committee.
The U.S. Supreme Court begins a new term on Monday amidst a raging political battle over an open seat and a high-stakes push by President Donald Trump to have the justices adjudicate a possible contested election.
"Lurking in the background is the possibility this could become the most tumultuous and divisive term since the Supreme Court decided Bush v. Gore 20 years ago," said Irving Gornstein, executive director of the Supreme Court Institute at Georgetown University.
The court will convene as a panel of eight for the first time since the death of Justice Ruth Bader Ginsburg as they await confirmation of Trump nominee Amy Coney Barrett, hearing oral arguments via teleconference that will be livestreamed to the public because of the coronavirus pandemic.
The justices face a fall docket of cases with implications for millions of American families and some of the nation's biggest businesses. They'll address matters of health insurance, use of force by police, military rape claims, religious freedom, grand jury secrecy, robocalls and faith-based foster care.
At the top of the list is a challenge to the Affordable Care Act brought by Texas and 18 Republican-led states backed by the Trump administration to completely invalidate the law, including protections for people with preexisting conditions. It will be argued Nov. 10 and decided by the end of June 2021.
"The stakes of this case have become only higher amidst the global pandemic. One estimate suggests there are 20 million people taking advantage of the exchanges," said University of Chicago law professor Jennifer Nou.
More on other key questions the court will consider this term can be found here.
-ABC News' Devin Dwyer
Democratic nominee Joe Biden and running mate Sen. Kamala Harris have faced growing pressure from Republicans to say whether they'd try to 'pack' the Supreme Court if Democrats were to win the White House and control of Congress in November, after both candidates have repeatedly dodged questions on the issue.
"You will know my opinion on court-packing when the election is over," Biden has said. "The moment I answer that question, the headline in every one of your papers will be about that rather than focussing on what's happening now. This election has begun. There's never been a court appointment once the election has begun."
What does it mean to 'pack' the Supreme Court?
The idea of adding more justices -- or what critics call "packing" the court to secure a desired majority -- is not unprecedented but has taken on new life with the death of Justice Ruth Bader Ginsburg and the Senate confirmation hearing for Judge Amy Coney Barrett.
Some Democrats -- including Senate Minority Leader Chuck Schumer -- and progressive groups have threatened to try to add justices to counter the effort by President Donald Trump and Senate Republicans to get Barrett confirmed before Election Day.
So, can a party in power really "pack" the court?
-ABC News' Devin Dwyer
The four days of Supreme Court confirmation hearings held by the Senate Judiciary Committee will look vastly different than previous hearings because of COVID-19 restrictions.
Sen. Mike Lee, R-Utah, and Sen. Thom Tillis, R-N.C., tested positive for the coronavirus after attending the White House Rose Garden ceremony to announce Barrett's nomination. As a result, members have the option of participating in the hearings remotely. Barrett is expected to appear in person, Lee is "undecided" and Tillis said Tuesday on Fox News that he anticipated attending some days of the hearing virtually.
On Friday, Sens. Kamala Harris, D-Calif., Patrick Leahy, D-Vt., and Cory Booker, D-N.J., sent a letter to Graham demanding "stringent" testing for all those in attendance. Sen. Joni Ernst, R-Iowa, tweeted that she also supported testing for members. But Graham has not responded.
Leahy, who is 80 years old, has decided to stay away from the hearings because of Graham's failure to respond. He and Harris have said they will participate remotely as a result.
Democrats are expected to mount additional challenges to safety of the hearing's proceedings, an official confirmed to ABC News.
Masks are now a mainstay of hearings on the Hill.
Long lines of spectators snaking through the halls of the Hart Senate Office Building waiting to get a glimpse of the proceedings will also be gone as the public will not be allowed inside. Only members, Barrett's guests, staff and journalists will be permitted.
Members who do appear will do so in bursts, an official confirmed to ABC News. They may appear to question Barrett but must return to their offices to watch the remainder of the hearing from a more isolated location.
-ABC News' Allison Pecorin
