It's offensive to disrespect Sen. Dianne Feinstein. She's 84, female and essential. She's been an indispensable senator on guns, terror and intelligence matters. Why must her own party treat her like a pox?

Melinda Henneberger | Opinion columnist

One of the country’s most powerful voices against assault weapons and 30-round magazines is long past her teen years. But like the young survivors of the school shooting in Parkland, Fla., she does happen to have been baptized in blood on this issue.

It was 1978 when Dianne Feinstein found her San Francisco Board of Supervisors colleague Harvey Milk face down in his own blood (“I tried to get a pulse and put my finger through a bullet hole”). In the decades since, the senior senator from California has authored the 1994 Federal Assault Weapons Ban, let the American public know what our government did in our name in the war on terror, and corrected disinformation about how the Russia probe began.

So must her own party treat her like a pox? Apparently, yes: At their recent state convention, her fellow Democrats denied her their endorsement. Among the reasons cited? Her support of the Iraq War. In 2002. “Time’s up!” the crowd chanted as she was played off the stage.

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As every story about 84-year-old Feinstein notes, she is the Senate’s oldest member. But because she’s also one of its most essential, the disrespect she’s being shown is offensive. (And though women tend to outlive men, is her age somehow more disqualifying because of her gender?)

Yes, she’s a moderate in a lapis-blue state, and as a young volunteer in San Francisco’s Mission District during the time she was mayor, I wrote her off as an all-in gentrifier, conveniently convinced that the problems of homelessness would one day evaporate like fog in the Presidio. Last year, when she insulted the Catholic judicial nominee Amy Coney Barrett by noting that “the dogma lives loudly within you,” I thought about getting the t-shirt.

Except, there’s no surplus of elected officials of any age who are as able on a number of matters that matter. And it isn’t as though she’s coasting on accomplishments long forgotten.

Before the 2016 election, Feinstein alerted the country to the danger of Russian interference (we didn’t listen, but she did tell us). Last year, she raised the specter of U.S. internment camps at Attorney General nominee Jeff Sessions’ confirmation hearing, then slipped out to have a pacemaker put in.

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Her unilateral decision to release the Fusion GPS transcript, over the objections of Republicans, was an important corrective. As ranking member of the Senate Judiciary Committee, she took it upon herself to let the public see the truth about the committee’s interview with the co-founder of the firm that did research on Donald Trump during his campaign. This was vital not because it helped her party, but because it refuted metastasizing falsehoods about the origins of the Russia probe.

“The innuendo and misinformation circulating about the transcript are part of a deeply troubling effort to undermine the investigation into potential collusion and obstruction of justice,” she said in a statement. “The only way to set the record straight is to make the transcript public.” The move prompted President Trump to call her "Sneaky Dianne Feinstein." But someday, even the GOP may thank her.

Meanwhile, no one can say she’s lost any of her gusto in her work. Seated at the president’s elbow as he unexpectedly — to see what Sen. John Cornyn looked like in cardiac arrest, maybe? — talked about banning assault weapons, she did the happy dance in her chair.

Feinstein's primary opponent, California Senate leader Kevin de León, whom she’s dominating in polls, said at the state convention that “I’m running because California’s greatness comes from acts of human audacity, not congressional seniority.”

But audacity she's got. And it's refreshing that she knows what to do with it.

Melinda Henneberger, a member of USA TODAY's Board of Contributors, is an editorial writer and a columnist for The Kansas City Star. Follow her on Twitter: @MelindaKCMO.