WASHINGTON — Justice Amy Coney Barrett, 52, is the youngest member of the Supreme Court and the junior member of its conservative supermajority. Last week, she completed what was only her third full term.

Yet she has already emerged as a distinctive force on the court, issuing opinions that her admirers say are characterized by intellectual seriousness, independence, caution and a welcome measure of common sense.

In the term that ended last week, she delivered a series of concurring opinions questioning and honing the majority’s methods and conclusions.

She wrote notable dissents, joined by liberal justices, from decisions limiting the tools prosecutors can use in cases against members of the Jan. 6 mob and blocking a Biden administration plan to combat air pollution. And she voted with the court’s three-member liberal wing in March, saying the majority had ruled too broadly in restoring former President Donald Trump to the Colorado ballot.

The bottom line: Barrett was the Republican appointee most likely to vote for a liberal result in the last term.

That does not make her a liberal, said Irv Gornstein, executive director of Georgetown University’s Supreme Court Institute.

“Don’t forget,” he said, “she voted to overrule Roe v. Wade. She voted to outlaw affirmative action. She almost always votes against the administrative state. And she voted to reject every voting rights challenge.

“Yes,” Gornstein added, “she is more principled and open-minded and thoughtful than some of the others. She cares more about precedent than some of the others. She is not as enamored with history and tradition as some of the others. But that’s as far as it goes.”

Still, some conservatives are alarmed, comparing Barrett unfavorably with the other two Trump appointees, Justices Neil Gorsuch and Brett Kavanaugh. Both men had served on federal appeals courts for more than a decade before joining the Supreme Court. Barrett spent most of her career as a law professor at the University of Notre Dame and sat on the federal appeals court in Chicago for just shy of three years.

While there, she wrote only one opinion of note, a dissent in a Second Amendment case, Josh Blackman, a law professor at South Texas College of Law Houston, asserted in a blog post. She arrived at the Supreme Court unformed and untested, he added, making her susceptible to persuasion by the savviest member of its liberal wing, Justice Elena Kagan.

“Gorsuch and Kavanaugh are not cut from the same block of wood as Barrett. Barrett was a piece of unfinished wood, and Justice Kagan is coating her with one layer of glossy lacquer after another,” Blackman wrote.

Barrett was rushed onto the court by Trump and Senate Republicans after the death of Justice Ruth Bader Ginsburg, a liberal icon who died in September 2020. Barrett joined the court the next month, just before the presidential election.

“You have a long history of believing that your religious beliefs should prevail,” Sen. Dianne Feinstein, D-Calif., told her during her 2017 confirmation hearings to the appeals court. She added, “The dogma lives loudly within you.”

That phrase became a slogan in the culture wars, embraced by social conservatives and appearing on T-shirts, tote bags and coffee mugs. It helped propel her to the Supreme Court.

At her 2020 confirmation hearings, Democrats called her a certain vote to overrule the Affordable Care Act, President Barack Obama’s 2010 health care law, and worried that she would favor Trump in litigation over the election that year.

Barrett’s record so far has not confirmed their worst fears. She has mostly voted in favor of claims of religious freedom. But in a concurring opinion in her first term in 2021, she rebuffed a request to overrule an important 1990 precedent that limits First Amendment protections for religious practices.

Justices Clarence Thomas, Samuel Alito and Gorsuch said they were ready to overturn the decision, Employment Division v. Smith.

Barrett was sympathetic but wary, writing that the court should not sweep aside a precedent unless it has a fully realized alternative. “I therefore see no reason to decide in this case whether Smith should be overruled, much less what should replace it,” she wrote.

Her opinion struck another note that would become familiar. While she says she is an originalist, seeking to discern and follow the original public meaning of the Constitution, she is keenly aware of the limits of historical evidence. “While history looms large in this debate,” she wrote, “I find the historical record more silent than supportive.”

Democrats’ unease about the Affordable Care Act turned out to be misplaced. Barrett joined a seven-justice majority in 2021 to deny the third major challenge to the law, on a theory that would come to play a significant role in her jurisprudence: that the plaintiffs had not suffered the sort of injury that gave them standing to sue.

That was the ground on which the court preserved the widespread availability of an abortion pill and the basis of one of Barrett’s majority opinions last month. In that case, Murthy v. Missouri, she rejected on standing grounds a Republican bid to prevent the government’s communication with social media platforms to combat what it said was misinformation. Thomas, Alito and Gorsuch dissented.

In the fall of 2020, just after Ginsburg’s death, Trump suggested that his third nominee would help him gain a second term. “I think this will end up in the Supreme Court,” he said of the 2020 election. “And I think it’s very important that we have nine justices.”

But Barrett recused herself from election cases that arrived at the court as emergency applications that October. A court spokesperson explained that she did so “because of the need for a prompt resolution” and “because she has not had time to fully review the parties’ filings.”

And when the court rejected a lawsuit by Texas in December that sought to throw out the election results in four battleground states, its unsigned order did not indicate that any of Trump’s three appointees had dissented. Alito, joined by Thomas, issued a brief statement on a technical point.

In the current election year, Barrett has written concurring or dissenting opinions in all three decisions involving or affecting Trump.

Derek T. Muller, a law professor at Notre Dame, said the nature of Barrett’s jurisprudence is evident from an assessment of the whole of her work on the court. “She’s intellectually independent,” Muller said, “but still thoroughly a conservative.”