Hillary Clinton, Varun Anand, Nick Merrill, Brian Fallon

Robby Mook (left, behind Hillary Clinton) tends to stay in the background, but he's a powerful voice in the campaign.

(The Associated Press)

The email hacking of the Democratic National Committee and Hillary Clinton campaign chairman John Podesta so far has offered up little more than political-insider gossip, such as a Bill Clinton aide calling the Clintons' daughter Chelsea a "spoiled brat."

But it also might have revealed the progressive movement's next star: Clinton campaign manager Robby Mook.

The unassuming 36-year-old Columbia University grad's success in politics, the Los Angeles Times wrote in July, "reflects the changing nature of campaigns, in which swashbuckling strategists are becoming less of an asset than disciplined data nerds who can build a loyal and effective campaign operation the way a seasoned Silicon Valley entrepreneur might."

That's surely true, but the hacked emails -- being dribbled out by the anti-secrecy website WikiLeaks -- show that Mook is much more than a data nerd targeting precincts that should get more or less voter-turnout attention. He's also a powerful policy advocate, one who appears to be even more in tune with Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren than the notoriously middle-of-the-road Clinton.

"It was gratifying to see that when nobody was looking, Clinton insiders had immense respect for Sen. Elizabeth Warren and her bold progressive ideas -- a positive indicator of the strong voice the Warren wing will hopefully have in a future Clinton administration," Progressive Change Campaign Committee co-founder Adam Green said in a statement today. "On numerous issues, including opposing the TPP, campaign manager Robby Mook took the boldest and most progressive position internally -- positions that ultimately won the day."

Green is referring to various emails from and about Mook concerning the controversial Trans-Pacific Partnership trade agreement and policy meetings between Clinton and Warren. An example: Clinton national-security adviser Jake Sullivan points out in one email that Mook believes Clinton should "lean more heavily and decisively against TPA and TPP," which Clinton ended up doing.

TPA is Trade Promotion Authority, the fast-track trade-negotiation power for the president. The still-in-the-works Trans-Pacific Partnership, meanwhile, is opposed by both Clinton and Republican nominee Donald Trump and supported by President Obama.

Despite the relatively benign disclosures thus far, the Clinton campaign has refused to authenticate the emails WikiLeaks has released. The U.S. intelligence community concluded the Russian government is behind the hack. The Russians are old pros at disinformation, raising the possibility that emails WikiLeaks has released or will release include some faked information.

-- Douglas Perry