It also promises to upend the relative ideological balance that has marked the court for decades, establishing a clear conservative majority should Trump's nominee be seated.
"Judge Barrett was confirmed to the circuit court three years ago by a bipartisan vote. Her qualifications are unsurpassed. Unsurpassed and her record is beyond reproach. This should be a straightforward and prompt confirmation," Trump said during the Rose Garden announcement.
He added, "Rulings that the Supreme Court will issue in the coming years will decide the survival of our Second Amendment, our religious liberty, our public safety and so much more. To maintain security, liberty and prosperity, we must preserve our priceless heritage of a nation of laws. And there's no one better to do that than Amy Coney Barrett."
Upon her nomination, Barrett said, "I love the United States, and I love the United States' Constitution. I'm truly humbled by the prospect of serving on the Supreme Court."
A devout Catholic, mother of seven and the favored choice of conservative groups, Barrett is a relative newcomer to the federal bench, having served just three years on the Chicago-based 7th Circuit Court of Appeals. Despite her short tenure as a federal judge, the longtime Notre Dame Law professor emerged as the front-runner on Trump's shortlist in the days following Ginsburg's death.
At 48, Barrett is the youngest Supreme Court nominee since Clarence Thomas in 1991, and could expect to serve well into the middle of the century – an attractive prospect to Trump and his allies on Capitol Hill.
Barrett's appeal within the administration has also been shaped in part by her reputation as a protégé of the late Justice Antonin Scalia, an icon of the religious right for whom she once clerked, sources said.
For Democrats, Barrett's conservative tilt and religious affiliation – expressed largely through her prolific catalog of scholarly writings – made her approval to the federal bench in 2017 a bitter affair. During a combative confirmation hearing for the post, Barrett became a rock star in conservative circles – not for what she told the committee, but what a powerful Senator said to her.
"Whatever a religion is, it has its own dogma. The law is totally different," said California Sen. Dianne Feinstein, the committee's ranking Democrat. "I think in your case, professor … the dogma lives loudly within you, and that is of concern."
Feinstein's comments drew rebukes from religious freedom groups and Republican senators. Her phrase, "the dogma lives loudly within you," has since made its way onto tee shirts and mugs for sale on the internet.
During the same hearing, Barrett said, "I take my faith seriously and I'm a faithful Catholic," but assured senators that it is "never appropriate to impose a judge's personal convictions, whether they arise from faith or anywhere else, on the law."
Professor Rick Garnett, a former colleague and Barrett's neighbor, said the "grace" with which Barrett fielded Feinstein's remarks appealed to religious conservatives and improved her standing with those in the administration.
"The way she handled that [hearing] elevated her in the public conversation," Garnett told ABC News. "It's not just that some of the senators said some strange things about religion, but it was that then-Professor Barrett handled it in a dignified way and I think it made a lot of Americans – religious believers of all stripes – feel inspired and proud."
Eventually, the Senate approved her nomination 55-43, with just three Democrats voting across party lines.
A self-described originalist, Barrett's tenure as an appellate judge has affirmed her conservative credentials. She authored a 2018 dissent arguing that convicted felons should not be barred from having guns. And while she has not issued a ruling yet on abortion, she has twice staked out positions aligned with the anti-abortion movement.
Prior to her judgeship, Barrett made a name for herself at Notre Dame Law School, also her alma mater. During her 2017 confirmation process, her Notre Dame Law colleagues penned a glowing – and unanimous – endorsement letter. More than 450 former students also advocated her confirmation.
She supplemented her time in the classroom – where she taught courses on federal courts, constitutional law, and statutory interpretation – with several scholarly articles on subjects ranging from Supreme Court precedent to due process.
In her scholarly work, Barrett has argued for Catholic judges to recuse themselves from death penalty cases, citing the "the moral impossibility of enforcing capital punishment," and suggested that legal precedent is susceptible to being overturned, leading critics to question how she would consider the landmark abortion ruling Roe v. Wade. In 2013, Barrett was quoted in the Notre Dame student newspaper as saying that "it is very unlikely at this point that the court is going to overturn Roe [v. Wade]."
During the 2017 confirmation, Barrett walked back her position on the death penalty, telling senators that she would not recuse "as a blanket matter" from capital punishment cases. On abortion, she stood by past comments that "abortion … is always immoral," but added that, if confirmed, her "views on this or any other question will have no bearing on the discharge of [her] duties as a judge."
Scrutiny of Barrett's faith has also extended to her personal affiliations, particularly her longtime ties to a Charismatic Christian community called People of Praise.
The group encourages its more than 1,700 members to make a covenant to the community, and it also assigns younger members a personal mentor, known as a "head" or "leader." Until recently, women in those roles were referred to as "handmaids," which led some news outlets and commentators to speculate that People of Praise may have been the inspiration behind Margaret Atwood's famous novel, "The Handmaid's Tale." Both Atwood and People of Praise denied those claims.
Barrett has not spoken publicly about her involvement in People of Praise, and neither the group nor an aide to Barrett would comment on her current status with the organization. Critics suggest her ties to the community and a covenant many members make – which the group describes as "a promise of love and service we choose to make to one another" – may conflict with her oath to uphold the constitution. For its part, People of Praise denies that its practices would have any effect on a member's professional life.
Barrett's confirmation process is expected to be strained by the political pressure of a nomination and hearing so close to a presidential election.
Democrats have accused Republicans of hypocrisy in moving forward with a replacement for Ginsburg, who died last week with only 45 days before the November vote. In 2016, Republicans blocked President Barack Obama's Supreme Court nominee, Judge Merrick Garland, after Scalia's death more than 200 days before the election.
A native of Louisiana, Barrett attended Rhodes College in Memphis, Tenn., for undergraduate studies before earning her law degree summa cum laude from the Notre Dame in 1997. After graduating law school, Barrett clerked for Judge Laurence Silberman of the D.C. Circuit Court of Appeals and then Scalia before a brief stint in private practice in Washington, D.C.
Her husband, Jesse Barrett, served as an Assistant U.S. Attorney in the Northern District of Indiana.