If confirmed, Barrett, a conservative jurist appointed by Trump in 2017 to the 7th US Circuit Court of Appeals, will certainly tilt the high court further rightward for years to come.
Here are some of Barrett's most notable writings:
In 2019, Barrett dissented alone when a 7th Circuit panel majority rejected a Second Amendment challenge from a man found guilty of felony mail fraud and prohibited from possessing a firearm under federal and Wisconsin law.
"History is consistent with common sense: it demonstrates that legislatures have the power to prohibit dangerous people from possessing guns," she wrote in Kanter v. Barr, applying an originalist approach that looked to the 18th-century intentions. "But that power extends only to people who are dangerous. Founding legislatures did not strip felons of the right to bear arms simply because of their status as felons."
Barrett concluded, "Holding that the ban is constitutional ... does not put the government through its paces, but instead treats the Second Amendment as a second-class right."
In June, Barrett dissented as a 7th Circuit panel left intact a US district court decision temporarily blocking a Trump policy that disadvantaged green card applicants who apply for any public assistance. In dispute were federal immigration regulations regarding when an applicant would be deemed a "public charge" and ineligible for permanent status in the US.
In her dissent, Barrett wrote that the Trump administration's interpretation of the relevant "public charge" law was not "unreasonable."
"At bottom, the plaintiffs' objections reflect disagreement with this policy choice and even the statutory exclusion itself. Litigation is not the vehicle for resolving policy disputes. Because I think that DHS's definition is a reasonable interpretation of the statutory term 'public charge,' I respectfully dissent," she wrote.
The 7th Circuit majority in Cook County v. Wolf countered that Barrett's construction failed to take account of the immigrants who would "bear the brunt of the" new rule.
In 2018, when the full 7th Circuit declined to reconsider a dispute over an Indiana abortion regulation requiring that the post-abortion fetal remains be cremated or buried, Barrett dissented with fellow conservatives. They began by focusing on a more contentious provision that had been earlier invalidated and not subject to the appeal.
That provision made it unlawful for physicians to perform an abortion because of the race, sex or disability of the fetus. Barrett joined a dissent written by Judge Frank Easterbrook referring to the law as a "eugenics statute."
"None of the Court's abortion decisions holds that states are powerless to prevent abortions designed to choose the sex, race, and other attributes of children," the dissent added.
Affordable Care Act
In an early 2017 law review essay, reviewing a book related to the Supreme Court ruling on the Affordable Care Act, Barrett criticized Chief Justice John Roberts' rationale that saved the law in 2012.
"Chief Justice Roberts pushed the Affordable Care Act beyond its plausible meaning to save the statute," Barrett wrote. "He construed the penalty imposed on those without health insurance as a tax, which permitted him to sustain the statute as a valid exercise of the taxing power."
At another point, Barrett refers to "Roberts' devotion to constitutional avoidance."
The court is scheduled to take up the latest challenge to Obamacare on November 10.
This story has been updated with additional developments.
CNN's Ariane de Vogue and Dan Berman contributed to this report.