I don’t know Justice Ginsburg. Like anyone who covers the Court, however, I am fascinated by this woman warrior with the body of a sparrow and the heart of a lion. Now 81 (Chemerinsky’s column ran the day after her birthday), she has survived both colon and pancreatic cancer (last month marked the fifth year after her most recent cancer surgery). Her voice at oral argument is sometimes indistinct. At other times she appears to doze.

But woe betide the advocate who believes that she is not listening, or who underestimates her knowledge of the record! Her questions are aggressive and insightful, and her written opinions are more vigorous than ever.

Here, based on no inside information whatsoever, is my guess about the mind of Justice Ginsburg in the final stage of her career.

First, she loves her work on the Court. She rarely misses a day on the bench. Once she sat through argument with a broken rib; when her beloved husband of 56 years, Martin Ginsburg, died, she was on the bench, announcing an opinion, 24 hours later.

And her work has gotten more interesting recently. Since the retirement of Justice John Paul Stevens in 2010, she has been the senior justice on the liberal side of the Court. This is an important job—when the Court’s conservatives vote together as a five-member bloc, the senior liberal justice assigns the task of preparing the liberal dissent. The purpose of such a dissent is to discredit the majority’s reasoning and offer future courts grounds to distinguish or overrule the case. Ginsburg often assigns that duty to herself; her major dissents are masterpieces of the genre.

If she were to retire at the end of this term, that leadership role would, for the next few years, fall to Justice Stephen Breyer, 75. (Chemerinsky also suggests that Breyer “consider” stepping down.) Though Ginsburg and Breyer are both “liberals” on this Court’s spectrum, they are a study in contrasts. Where Ginsburg fights, Breyer dithers; where her ideas are clear, his are mercurial; where she draws lines, he wanders across them; where her dissents are straightforward, his tend to be—well—incomprehensible. In the showdown over the Affordable Care Act, Breyer, along with Justice Elena Kagan, crossed the aisle to support Chief Justice John Roberts in limiting Congress’s Spending Power; Ginsburg’s s opinion dripped contempt for this newly minted limit on a crucial federal power. I wouldn’t be surprised if she thought that her departure would leave the liberal wing without real leadership.

Beyond loving her work, of course, it is the melancholy fact that she has little else in her life. By all accounts, “Marty” Ginsburg was a Sun King figure, a gourmet cook and entrancing host, beloved by a wide circle of friends, devoted to his brilliant wife, bubbling with joy and humor. Ruth Ginsburg’s air is often dour, but she has a joyous side. (See the brilliant profile by The Washington Post’s Robert Barnes from last September.) Marty expressed it.