When the history books are written, Rod Rosenstein might just be the most interesting figure of the Russia investigation—the beleaguered deputy attorney general whose memo in his first days on the job was used to justify the firing of James Comey.

After that he quickly appointed Robert Mueller as the special counsel and spent the following year supervising his investigation while under immense pressure from President Trump and congressional wolves seeking to undermine his credibility, even impeach him.

As congressional Republicans have sought to undermine the Justice Department’s integrity and independence, Rosenstein has made numerous short-term, tactical concessions to his critics, bending traditional rules and handing over documents to Congress about confidential sources and ongoing investigations—compromises that previous administrations would never have made.

Why would anyone put up with the abuse, vitriol, and daily haranguing from the president’s Twitter account that Rosenstein has endured? Why would Rosenstein seemingly set precedents that undermine the core principles of the Justice Department, an institution that he’s devoted nearly his entire career to serving?

I have a simple theory: In a world of hedgehogs and foxes, Rosenstein today is the ultimate hedgehog.

Rosenstein knows one very big, monumental, history-shaping thing—how Trump’s presidency will end—and he’s wagered that if he can hang on long enough, justice will be done and the good guys, in his eyes, will win. His early actions, around Comey’s firing, will be vindicated by history when seen by the light of his bravery and personal sacrifice and refusal to be bullied into quitting, a move that would almost surely lead to Mueller’s investigation being shut down or circumscribed by whichever Trump appointee takes over supervising it next.

Deputy Attorney General Rod Rosenstein knows what he’s protecting by staying in his job and fighting each day to preserve Mueller’s investigation Alex Wong/Getty Images

Remember, Mueller is keeping Rosenstein informed and has returned to him regularly for briefings, to ask for permission to expand his investigation in key ways, and to hand off parts of the investigation to other Justice Department units. Which is all to say: Rosenstein knows how the next dominoes fall.

Which means Rosenstein knows what he’s protecting by staying in his job and fighting each day to preserve Robert Mueller’s investigation—and to ensure it has the time to come to a public denouement that he surely already knows. Rosenstein is fighting a guerilla war against Republicans on Capitol Hill and Donald Trump, knowing that he can lose lots of small battles because ultimately he will win the war.

The reason that Rosenstein has stayed on appeared to be on full display Friday, as he—and he alone—announced the historic indictment of 12 Russian military intelligence officers responsible for the 2016 attacks on the presidential election. It was only the second time Rosenstein has personally issued the special counsel’s indictments, the other being February’s equally monumental indictment of the Russians involved in the Internet Research Agency’s social media campaigns during the election.

It was hard not to view Friday’s press conference as a victory lap of sorts by Rosenstein, as he announced that the US government had proof beyond a reasonable doubt that the Russian military attacked American democracy—an announcement he made just one day after a marathon, 12-hour Republican congressional pigpile on the FBI agent, Peter Stzok, who helped launch that very investigation and execute it in secret throughout the fall 2016 campaign.

The highly detailed, 29-page indictment of 12 Russian military intelligence officers was a reminder, too, of the incredible level of detail known by Special Counsel Robert Mueller’s team.

The sheer volume of what Robert Mueller knows is staggering. Perusing his various court filings since last September makes clear he knew the individual changes Paul Manafort made in a specific Microsoft Word document; he knew that Dutch lawyer Alex van der Zwaan was lying about what he did on behalf of Manafort and Gates; he knew the specific times Russia military intelligence officers were searching specific words way back in 2016; he knew the specific cryptocurrency transactions used to register the Russian intelligence agency accounts; he knows what the hired trolls at the Internet Research Agency were writing in emails to their family members in 2017; he knew the messages Manafort was sending on encrypted messaging services.

Former Trump Campaign Chairman Paul Manafort faces a series of indictments brought by the special counsel for money laundering and is scheduled for trial next month. Zach Gibson/Bloomberg/Getty Images

Even those who think they know turn out to be surprised by the scale and specificity of what Mueller knows. Last month, the senior Democrat on the Senate Intelligence Committee, Mark Warner, joked to donors, “If you get me one more glass of wine, I’ll tell you stuff only Bob Mueller and I know. If you think you’ve seen wild stuff so far, buckle up. It’s going to be a wild couple of months.” But after Friday’s indictment, Warner said—impressed—that the “vast amount of information” in Mueller’s latest documents were new to him and the Senate Intelligence Committee.