Sidney Blumenthal arrives to face questions from a Republican-led House panel in June. (Susan Walsh/Associated Press)

The latest batch of Sid-grams dropped on Friday, like Halloween candy for a community of junkies that had gone a full week without a fix — the Benghazi inquisitors, the Hillary nuts, the Beltway journalists who’ve spent 30 years looking askance at that sharp-elbowed insider named Sidney Blumenthal.

One e-mail to then-Secretary of State Hillary Rodham Clinton was a “confidential” memo from October 2011 about the whereabouts of Moammar Gaddafi.

Another was a link to a news story about the wedding of Blumenthal’s 86-year-old mother.

“This sounds credible,” Clinton responded to the first.

“That is fabulous — mazel tov!” Clinton responded to the second.

The Sid-grams swing between the casual and the formal.

One was a fawning update on her poll numbers.

Another was the draft of a speech apparently written or edited by Blumenthal in July 2009 that bears a resemblance to a speech Clinton gave the following week at the Council on Foreign Relations.

In the river of Clinton e-mails that’s been flowing since May, “Sid” is a frequent sender and recipient. His e-mail address begins with “SBWHOEOP,” a cocktail of his initials and the White House e-mail domain “@who.eop.gov.” It seems this ex-adviser to President Bill Clinton wanted to preserve the West Wing cred he surrendered at the turn of the millennium.

Now his private attempt to stay relevant to the Clintons has yielded a very public relevance in the latest scandalization of Hillary.

“I think he is, in some ways, a public intellectual who is also capable of being — and I don’t mean this in the bad sense of the word — a propagandist,” says longtime Democratic political consultant Bob Shrum, a friend of Blumenthal’s. “He’s trying to advance a message. And he’s deeply loyal to the Clintons.”

Blumenthal’s name was mentioned dozens of times in last month’s congressional hearing on Benghazi and hundreds of times since then — in columns, on morning shows, on talk radio and now in this very piece you’re reading.

To partisans, he’s either the polestar of Clintonian malfeasance or a symptom of Republican mania. From the subject lines of his e-mails, though, “Sid” just seems like a pal who’s always got the inside scoop.

“H: Great to see you. Drop in again.”

“Syria intel. also my mother out of hospital.”

“can you call me now? eureka idea for midterms!!”

“Useful insight,” Clinton typed, forwarding one such memo about Libyan politics to a State staffer. “Pls circulate.”

The conservative punditry saw evidence of conspiracy and corruption.

“Sidney Blumenthal appeared to be running State Department business,” said Wall Street Journal columnist Kimberley Strassel in May on Fox News, and referred to him as an “old Clinton crony.”

“Sidney Blumenthal has been, essentially, the secretary of state,” Rush Limbaugh said on his radio show in July, referring to him as a “reprobate” and “despicable person.”

Blumenthal’s friends in the media rushed to his defense.

“Having known Sid for nearly 40 years . . .” Joe Conason began in a Politico piece, saying that Blumenthal’s enemies “have concocted an image of him that is strangely flat and cliched.”

“I’ve known Sidney Blumenthal since we were aspiring reporters together in our 20s,” wrote James Fallows in the Atlantic, before praising Blumenthal’s writings.

The State Department brushed off the Sid-grams as “unsolicited thoughts.”

“I have many, many old friends, and I always think that it’s important when you get into politics to have friends you had before you got into politics, to understand what’s on their minds,” Clinton said in Iowa in May.

Never mind that the two met in 1987, while Clinton was first lady of Arkansas and Blumenthal was a reporter for The Washington Post, and got to know each other during Bill’s 1992 presidential campaign.

Blumenthal, through his publisher Simon & Schuster, declined to comment for this article, but thanks to his correspondence with Clinton and his 40 years of journalism, he’s an open book:

He grew up on the North Side of Chicago, the oldest of three in a four-newspaper household, a bookish boy who could still punch out an older bully. John F. Kennedy’s 1960 campaign stop in Chicago was his entree into politics, he recalled in his 2003 memoir, “The Clinton Wars.” Blumenthal, as a 12-year-old Democratic volunteer, went door-to-door on Election Day to coax voters to the polls. Kennedy won Illinois by fewer than 9,000 votes, a razor-thin margin disputed by Republicans, and young Sidney felt like he’d contributed. He was hooked.

He finished high school at 16, graduated from Brandeis University as an American studies major in 1969 and started his journalism career at the tabloid weekly Boston After Dark. He covered Massachusetts politics during a decade when consultants took over the cycle, an evolution he codified in his first book, “The Permanent Campaign,” in 1980. He wrote about the 1984 presidential race for the New Republic. He spent a chunk of the 1980s at The Post, where his telephone conversations were loud enough for the entire Style section staff to know whenever he had a senator on the line.

Blumenthal quickly chafed fellow members of the D.C. journalism establishment, thanks to his closeness with Gary Hart, his loud skepticism about the Whitewater affair and his decision, in 1996, to leave the New Yorker to become a senior adviser to President Clinton. By then, he was already a kind of confidant to Hillary, who three years earlier had called him into her West Wing office to explain her version of Whitewater.

This kind of line-crossing is a common Washington racket. George Stephanopoulos went from the Clinton White House to ABC News, much the same path trod by Hill staffers Tim Russert and Chris Matthews into broadcast jobs. Robert Novak was a brutal, brilliant newsman who had the ear of the Republican establishment. Jay Carney was one of several journalists who joined the Obama press operation. But Blumenthal was the rare member of the press to jump directly into a policy role.

“Sometimes I’ve found myself overtaken by happenstance and sudden offers, and I have moved under my own steam to unexpected places,” Blumenthal wrote in “The Clinton Wars.” “You can never predict where events will take you, but I have never felt a severing of continuity. My experience has accumulated.”

And so the former door-knocker for Kennedy found himself a half century later — after using journalism to get in the door — with direct access to one former president and one maybe-future president. Last Friday’s e-mail dump continued to reveal his strategic mind. It also raised the volume on the ballad of Sid and Hillary.

“That’s the vulnerability of charisma,” Blumenthal wrote to her in 2009 about President Obama. “To protect it requires successful policies.”

“Back to writing legacy memo for Bill,” he closed one e-mail in January 2010, referring to his work for the Clinton Foundation.

His fluency in both spin and policy, his true-believer passion, his ruthless intelligence — all of these are likely reasons that the Clintons haven’t blocked his e-mail address.

“He is someone who has cultivated and nourished relationships with a wide array of people over the span of a long and just fascinating career,” says a former Republican campaign strategist who has been friends with Blumenthal for three decades. “That he’s been thrust into the light as a Fox News cartoon of a conspiracy-minded Democratic operative is, I think, painful for everybody who knows him, and especially for him and for [his wife] Jackie. You can’t talk about Sid as a human without ultimately coming back to his very unique insight into American politics and the way things work, which people really should respect and revere.”

Instead, the U.S. marshals knocked on Blumenthal’s door in May to deliver a subpoena from House Republicans. The person who answered was the only member of the household who was officially in politics at the time: Jackie Blumenthal, an elected neighborhood commissioner for the sliver of Glover Park that abuts the vice president’s residence at the U.S. Naval Observatory. One of her political triumphs, a neighbor says, was persuading the city to rearrange a dodgy intersection on 37th Street NW.

Sidney, meanwhile, is finishing the first book in his multivolume history of a fellow Illinois boy: Abraham Lincoln. The title is “A Self-Made Man.”