Former vice president Joe Biden has a lot to answer for. At least that is how his opponents for the Democratic presidential nomination have treated him, particularly during the primary debates. There's the Obama administration's deportation policies, Biden's support for the 1994 crime bill, his handling of the Clarence Thomas confirmation hearings, his position on mandatory busing in the 1970s, and so on.

For those of us following at home who aren’t necessarily familiar with every episode in Biden’s Forrest Gump-like career, it can be hard to keep up. It would help to have a guide, a Bidenologist, if you will — someone to provide the context that is often missing during each 30-second attack. Fortunately, such a person exists: political columnist Jules Witcover. He has covered Biden longer than perhaps anyone and, at the age of 92, has just published an update of his 2010 biography “Joe Biden: A Life of Trial and Redemption.”

Biden’s decision to run a third time for the presidency, Witcover argues, was fueled not only by his late son Beau’s well-known wishes he do so, or by mockery from President Trump (“Sleepy Joe”), but also by the notion that the former vice president thinks he can unite an increasingly divided Democratic Party. “He really recognized that when there was this competition between the so-called progressives and the old liberals, that situation was to his advantage because he had a foot in both camps,” Witcover told me.

Perhaps Witcover — who has written or co-written 19 books, and who still writes a syndicated column for Tribune newspapers three times a week — understands Biden so well because the two men have much in common, from their non-privileged backgrounds (Witcover calls Biden “Mr. Middle Class”) to their current roles in their respective professions. Like Biden, Witcover has continued to work long past the typical age of retirement. And he, too, has arrived in the final stages of his career as something of a throwback.

As a columnist, Witcover offers an old-fashioned, center-left liberalism, and cherishes bipartisanship in a time when bipartisanship is often a dirty word for younger progressives. As a biographer, meanwhile, he takes a judgment-free, straight-ahead approach that stands in contrast to much of today’s click-driven, hot-take-infused political writing. Witcover knows he’s old school — and so do his friends. “He’s the last of the mastodons!” the Atlantic’s Ron Brownstein told me last year. (At the time, Brownstein and I were colleagues at the Atlantic.) He heaped praise on Witcover’s work ethic and reportorial style.

Witcover was born in Union City, N.J., where his father owned and operated a one-man gas station. After attending Columbia University for college and graduate school, he meandered from newspaper to newspaper before landing a job covering Washington for the Newhouse newspaper chain. By the time he appeared in Timothy Crouse’s seminal account of the 1972 election, “The Boys on the Bus,” Witcover had, according to Crouse, gone from someone the Washington press establishment “had tended to slight” — because “he came from a lower-middle-class background and said ‘duh’ and not ‘the’ ” — to “among the most respected reporters in town.”

“I think at a time when mainstream political journalism was at its peak, there was no better practitioner than Jules Witcover, and there’s a whole body of work that few if any can ever equal,” Al Hunt, a Bloomberg columnist and former Wall Street Journal correspondent, told me. “And I think probably most of it stands the test of time in history pretty darn well, and that ain’t a bad legacy.”

The Biden camp also reveres him, it seems. Ted Kaufman, Biden’s longtime chief of staff who replaced him as U.S. senator in 2009, was a key resource in Witcover’s reporting for the book. “During the last 50 years, no one had been a more consistent source of excellent commentary on the political scene in the United States than Jules Witcover,” Kaufman told me through a spokesperson.

I asked Witcover what he thought of the similarities between him and Biden, and he was a bit taken aback. “I’ve never been compared to Joe Biden before!” he responded. “I think it’s happenstance. I don’t feel that I have any particular kinship with Joe Biden, although it is true we both come from working-class backgrounds. But I appreciate his candor and his decency. And I think that, in this election particularly, the matter of common decency is important.”

Witcover and I discussed the latest round of hurdles for Biden, who is still leading in most polls of the Democratic field. I asked how he thought Biden did in the first two debates (“I think he did okay, but he didn’t do great”) and the criticism he received from Sen. Kamala Harris about school busing. Witcover insists that Biden himself never supported segregationist policies but is taking the fall for his “modus operandi ... trying to work across the aisle and having friends in the other party, not collaborators, but people with whom he could deal.”

Witcover is both a workhorse and someone simply undeterred by old age. In conversation, he struggles to identify many hobbies beyond work (though he says he likes old movies). Even from his summer home in Bethany Beach, in Biden’s home state of Delaware, Witcover works just as hard as he does from Washington.

He described the question of Biden’s age (76) as “legitimate in terms of actuarial charts,” though he added, “It’s interesting that nobody is criticizing Bernie Sanders for being too old, and he’s a year older than Biden.” As for how Witcover’s own age has affected his craft: “I think I have better knowledge of politics and the craft of journalism after all these years, but like other people sometimes I find it harder to come up with a column than I used to,” he said. “But the thing about the deadlines is they’re very demanding and they don’t take into consideration anybody’s age or mental capacity.”

Witcover doesn’t want to come across as a “booster” or a “homer” for Biden, he said. He’s not necessarily rooting for anyone in the Democratic primary, but he feels Biden’s foray into the 2020 field is a net positive. “If Joe Biden as a strong voice in the Democratic conversation can somehow contribute to what should be a bipartisan effort to return normality back to American politics,” he wrote in an April column, “his decision to run will have been the right one, whether he wins the presidency or not.”

Scott Nover is a writer in Washington.