Supreme Court Justice Ruth Bader Ginsburg. (J. Scott Applewhite/AP)

Justice Ruth Bader Ginsburg was back on the bench Tuesday for the first time since her recent cancer surgery as the Supreme Court returned from its winter break and resumed hearing cases.

Ginsburg, 85, was the first justice to ask a question during the oral arguments in a case centering on whether the government could be considered a “person” able to challenge a patent. Just a minute after the arguments began, she asked the attorney for the company challenging the government a question clarifying its position. She asked a second question five minutes later.

For much of the time, Ginsburg remained still as her colleagues alternately leaned back in their seats, swiveled in place or rubbed their faces. Her head slightly bowed, she peered out over the court and appeared focused on the arguments. During the government’s response, she asked three more questions.

Ginsburg entered and left the courtroom without assistance. Her appearance seemed to be the main attraction for some of the journalists who gathered in the crowded courtroom; two quickly left once she had appeared and asked her first question.

Ginsburg missed January arguments after undergoing a pulmonary lobectomy Dec. 21 to remove two malignant nodules from her left lung. It was the first time the justice had missed oral arguments since she joined the court in 1993, even though she has had two bouts with cancer in that time.

The justice’s nearly two-month absence was about what most cancer specialists say should be expected of a person recovering from such a serious operation.

During the court’s hearings in January, Ginsburg worked from home reviewing briefings and arguments, and Chief Justice John G. Roberts Jr. said she would participate in deciding them.

She also has been involved in previous private conferences and was part of the majority when the court granted an emergency order blocking implementation of a restrictive Louisiana abortion law.

Other justices have missed time on the bench because of illness, but none had the heightened scrutiny of social media. Conspiracy theories about Ginsburg have proliferated on fringe right-wing websites, with some demanding to see “proof of life.”

Ginsburg attended a concert about her life sponsored by the National Constitution Center in Washington on Feb. 4, but those suspicious about her said they did not believe media reports about her appearance.

It is not uncommon for justices to participate in deciding cases when they have not attended oral arguments.

The most recent example was when then-Chief Justice William H. Rehnquist missed considerable time as he battled thyroid cancer. He missed more than 40 oral arguments, and Justice John Paul Stevens presided over the court while he was gone.

Rehnquist helped decide most of those cases and returned to the bench for the end of the term. He died Sept. 3, 2005. President George W. Bush nominated Roberts as his replacement.

In a pulmonary lobectomy, a lobe of the lung is removed. The right lung has three lobes, and the left has two.

Ginsburg was treated for colorectal cancer in 1999, and pancreatic cancer was discovered at a very early stage 10 years later. She scheduled treatment for both during the court’s off days and did not miss a day of oral argument.

She also has suffered broken ribs, several times, including last November after a fall in her chambers. That actually turned out to be lucky, as it was during treatment for that injury that the malignant modules were discovered.

Ginsburg has said repeatedly in interviews that she will continue in her role on the court as long as she feels she is able to do the job. She has hired law clerks through the 2020 term.

Her liberal supporters hope that she remains, partly to deny President Trump a chance to nominate a third Supreme Court justice. Justices Neil M. Gorsuch and Brett M. Kavanaugh were his first two choices.