Members of the Senate Judiciary Committee on Monday will begin the notoriously difficult job of trying pin down a Supreme Court nominee on specifics about how she would approach the job or confront the national issues in which the high court now increasingly plays an outsize role.

Jackson’s nomination is historic, as the first Black woman named to a court that for hundreds of years was populated only by White men. In the short term, her replacement of Justice Stephen G. Breyer, a man who once hired her as a clerk, would be unlikely to shift the court’s ideological balance or its six-justice conservative supermajority.

But justices generally serve for life, and they bring their own life experiences to the job. When senators questioning her on her nomination to the U.S. Court of Appeals for the D.C. Circuit asked about race, as President Biden had touted the diversity of his first judicial nominations, she shifted to her experiences as a public defender and trial judge.

“I’ve experienced life in perhaps a different way than some of my colleagues because of who I am,” she said, “and that might be valuable, I hope it would be valuable, if I was confirmed to the court.”

There are blank spaces in her résumé regarding some issues preoccupying the court, such as the Second Amendment. But her nomination by a president who favors gun control laws is a clue to those for whom the issue is paramount.

Biden has “nominated someone who we are confident will determine that common-sense gun safety laws are constitutional,” Shannon Watts, the founder of Moms Demand Action, said when Jackson was nominated.

The NRA Institute for Legislative Action, in contrast, saw trouble ahead. “Judge Ketanji Brown Jackson has never affirmed that the Second Amendment protects the individual, fundamental right of all Americans to keep and bear arms for the defense of themselves or others,” the group said in a statement.

There is more to go on in other areas, but it all comes with a caveat. Jackson has been applying the law of her circuit and the Supreme Court. As a justice, she will be free to advocate for changing precedent.

Abortion is already the dominant issue in the Supreme Court’s current term. The court voted 5 to 4 to allow a controversial Texas ban on most abortions to take effect while legal challenges continue. The law bans abortions after about six weeks and allows private individuals to enforce it. By the end of the term, the court will rule on a restrictive Mississippi law that would violate the precedents set by Roe v. Wade.

Jackson would enter the fray next term without much of a judicial track record on abortion. In a related case, she ruled against the Trump administration’s decision to cut grant funding under the federal Teen Pregnancy Prevention Program. In Policy and Research v. HHS, she found that the administration had not properly grounded its action in the mandates of the Administrative Procedure Act.

As a lawyer in private practice, Jackson wrote an amicus brief on behalf of women’s groups defending a Massachusetts law that kept abortion protesters away from the entrances of facilities. It was based on a Colorado buffer zone law that has been upheld by the Supreme Court. The Massachusetts law was upheld by the U.S. Court of Appeals for the First Circuit, and the Supreme Court denied review.

As President Donald Trump committed to nominating judges who he said would overturn Roe, President Biden has done the opposite. The Biden administration “is committed to codifying Roe v. Wade and appointing judges that respect foundational precedents like Roe,” the White House said in statement last year.

That has led abortion rights groups to praise Jackson’s nomination and those on the other side to oppose her. Both groups have reason to believe such proxies. While nominees always profess having open minds, the most recent Republican nominees to the high court have been open to restrictive state abortion laws, and the last two Democratic choices, Justices Sonia Sotomayor and Elena Kagan, have been unwavering supporters of abortion rights.

In two significant cases likely to surface during her hearing, Jackson upheld the investigative powers of Congress and rejected efforts by Trump to block testimony from a top adviser and the release of White House records.

She was part of a three-judge panel of the D.C. Circuit that denied Trump’s request to shield documents against scrutiny by the House committee investigating the Jan. 6 attack on the Capitol. The Supreme Court turned down Trump’s request to halt the ruling, with only Justice Clarence Thomas noting his dissent.

As a district court judge, Jackson also ordered Trump’s former White House counsel Donald McGahn to testify on Capitol Hill and rejected Trump’s argument that close advisers to the president are immune from congressional subpoenas.

“Presidents are not kings,” she wrote in a 118-page decision that said McGahn must comply with the subpoena related to the former special counsel’s investigation into Russian election interference.

The case was twice appealed to a full panel of the D.C. Circuit. It was not resolved by the courts before the Biden administration and House Democrats negotiated a settlement for McGahn to answer a narrow set of questions on Capitol Hill.

Jackson has often sided with labor unions, striking down key provisions of Trump administration orders in 2018 that would have made it easier to fire federal employees and weaken their representation.

Although the president has the power to issue executive orders related to federal labor relations, she wrote, “no such orders can operate to eviscerate the right to bargain collectively as envisioned” in the federal labor-management relations statute.

The collective bargaining process, she added, “is not a cutthroat death match.” A unanimous D.C. Circuit panel vacated the ruling the next year and said the district court lacked jurisdiction to decide the case.

In her first ruling as an appeals court judge in February, Jackson wrote a unanimous opinion invalidating a Trump-era policy that had restricted the rights of labor unions representing government employees to negotiate over working conditions.

Jackson sided with the unions, finding that a labor agency’s “choice to abandon 35 years of precedent” in changing its policies about when collective bargaining is required was “arbitrary and capricious” and violated federal law.

Cases involving affirmative action are somewhat rare, but the Supreme Court next term will hear one that might end even the limited use of race in admissions decisions for universities that say they need the information to build diverse student bodies.

There is little in Jackson’s background to indicate how she sees the issue. But the question she is likely to face at her confirmation hearing is whether she should be involved at all in the case, which arises from admissions policies at Harvard — the judge’s alma mater — and the University of North Carolina at Chapel Hill.

Jackson for six years has served on the Harvard Board of Overseers; her term ends this spring. The board provides “counsel to the University’s leadership on priorities, plans, and strategic initiatives,” its website says. In addition, Jackson’s youngest daughter will be a freshman at Harvard in the fall.

Some Republican senators already have expressed concerns about Jackson’s possible involvement in the case. She has been attentive to recusal issues in the past, removing herself from cases that even some legal ethicists saw as borderline. Recusals at the Supreme Court, however, bring different issues, as no other judge can step forward to weigh in, and an eight-justice court brings the chance of a 4-4 tie.

Jackson would be the first justice in decades with significant experience as a criminal defense attorney. Like Breyer, she would bring expertise in the intricacies of federal sentencing policy from her time as a member of the U.S. Sentencing Commission.

She has said that her tenure as a federal public defender in D.C., where she mostly handled appeals for poor people who had been convicted of crimes, informed the eight years she served as a trial court judge. Her experience gave her insight, she said, into how little most defendants understand about the law and their rights.

“They had just been through the most consequential proceeding in their lives, and no one really explained to them what they were supposed to expect,” Jackson said during her Senate hearing for the D.C. Circuit seat. “So, they didn’t know where things might have gone wrong.”

But that experience comes with a vulnerability. Republicans are expected to sharply question Jackson about her work as a public defender challenging the detentions of men held by the United States after the 9/11 attacks as “enemy combatants” in Guantánamo Bay, Cuba.

Jackson continued her work advocating for the rights of criminal defendants when she moved to private practice. She filed a Supreme Court brief successfully challenging the government’s procedures for holding Guantánamo detainees and briefs in a separate pair of cases over the rights of criminal defendants.

She also has personal experience with the criminal justice system. At her nomination announcement, Biden noted her family connection to law enforcement; two of her uncles were police officers, including one who became the police chief of Miami. Her brother was a detective in Baltimore.

Jackson noted another side: A different uncle was sentenced to life in prison under tough drug laws. After a referral from Jackson, a law firm helped him years later receive clemency from President Barack Obama.

On the bench and in her thorough, detail-oriented writings, Jackson has shown empathy. She took local prison officials to task for failing to accommodate a deaf inmate and ordered the D.C. Department of Corrections to pay damages to the man, William Pierce.

The District’s “willful blindness regarding Pierce’s need for accommodation and its half-hearted attempt to provide Pierce with a random assortment of auxiliary aids — and only after he specifically requested them — fell far short of what the law requires,” Jackson wrote.

In another high-profile decision, Jackson sentenced Edgar Maddison Welch, who commandeered the D.C. pizza restaurant Comet Ping Pong with a military-style rifle while seeking to investigate a viral Internet rumor. “I hope you understand and see how much people have suffered because of what you did,” she said in giving him a four-year sentence.

She added, “I am truly sorry you find yourself in the position you are in, because you do seem like a nice person who in your own mind was trying to do the right thing. But that does not excuse reckless conduct and the real damage that it caused.”

Jackson will be pressed by Republican senators to detail her “judicial philosophy” and the method of constitutional interpretation she favors. In her previous confirmation hearings, she has passed up the chance. “I do not have a judicial philosophy per se, other than to apply the same method of thorough analysis to every case, regardless of the parties,” she said in a written answer during her confirmation to the D.C. Circuit.

“Specifically, in every case that I have handled as a district judge, I have considered only the parties’ arguments, the relevant facts, and the law as I understand it, including the text of any applicable statutes and the binding precedents of the Supreme Court and the D.C. Circuit,” Jackson added. Such an answer is not as satisfying in the case of a Supreme Court nominee, who would have the chance to change the court’s precedents.

“Judicial philosophy is a key qualification for the Supreme Court,” Senate Minority Leader Mitch McConnell (R-Ky.) said in a statement on Jackson last week. “There are a lot of smart lawyers in our country. But they don’t all understand that a judge’s proper role is to apply the text of our laws neutrally. Some would rather start with liberal outcomes and reason backwards.”

But it is unlikely that any nominee would admit to that, and nominees are generally vague about their philosophies and the weight they assign to upholding past Supreme Court precedents, even those with which they may disagree.

In nominating Jackson, Biden said, “I looked for someone who, like Justice Breyer, has a pragmatic understanding that the law must work for the American people” and who understands “that the Constitution is a resilient charter of liberty.”

He added that the person would have “the wisdom to appreciate that the Constitution protects certain inalienable rights — rights that fall within the most fundamental personal freedoms that our society recognizes.”

Jackson sided with immigration advocacy groups that she said were likely to prevail and show that the expansion of the program would cause irreparable harm to many legal immigrants and asylum seekers who could be swept up and expelled from the United States without legal recourse.

Jackson said in a lengthy opinion that the Department of Homeland Security had “failed to address significant flaws in the expedited removal system” and that it ignored the impact of the expansion “on settled documented noncitizens and their communities.”

On appeal, the D.C. Circuit reversed the injunction, finding that such expedited removal decisions are within the homeland security secretary’s discretion. The appeals court agreed with Jackson on other grounds and sent the case back for review.