(Bloomberg Opinion) -- We don’t know what’s in it yet. But we can already say that the Mueller report is a win for democracy. We can say so definitely because on Friday afternoon, special counsel Robert Mueller officially filed a report with Attorney General William Barr on what he has learned about Russian interference in the 2016 election.

Lest we forget, that was far from a foregone conclusion throughout much of the past two years.

Despite President Donald Trump’s threats and extensive speculation about his firing the special counsel, political incentives turned out to be enough to keep Trump from pulling the trigger.

The main takeaway from the news that broke Friday evening, then, is that the Constitution is working. The separation of powers proved sufficient to get an independent review of Trump’s campaign and its conduct. And that happened even though the independent counsel law that Congress had passed in the wake of Watergate, and was used to investigate President Bill Clinton, was allowed to expire in 1999 and did not apply to Mueller’s investigation.

Given that there was no independent counsel law in place, it was technically up to the president to investigate himself. That sounds in the abstract like a terrible idea. And you would think that if the idea was bad in the abstract, it would be much worse when the president was Donald Trump, a man who has publicly speculated about pardoning himself and who has the most extensive theory of executive power in modern memory — or maybe ever.

Nevertheless, political pressure on Trump after the firing of FBI Director James Comey in May 2017 was enough to make Trump’s Department of Justice trigger the special counsel regulation that had been drafted during Barack Obama’s administration.

The logic behind that regulation was that political pressure, combined with the mild restriction that the executive agree not to fire the special counsel without good cause, would protect the investigator from presidential threat. That calculus turned out to be accurate.

It helped, of course, that Trump’s first attorney general, Jeff Sessions, had to recuse himself from the matter because he did not disclose contacts with a Russian official during his confirmation hearings. That recusal opened the door for Deputy Attorney General Rod Rosenstein, who has emerged as one of the heroes of this tumultuous period in U.S. history. Rosenstein chose Mueller, a figure notable for his nonpartisan stance and bipartisan reputation as an incorruptible straight-shooter, to lead the investigation.

It’s hard to think of another public figure in recent U.S. history who has been brought under as much presidential pressure in the public sphere as Mueller. Trump spoke and tweeted about Mueller and his staff hundreds of times — and almost without exception those presidential communications were aimed at undercutting the investigation. It will probably be decades before the term “witch hunt” can get back its good old-fashioned associations with the Salem trials and McCarthyism.

Mueller deserves tremendous credit for withstanding the pressure, whatever his report ends up saying. But in our appropriate rush to canonize Mueller in the pantheon of true public servants, we shouldn’t forget the constitutional structures that underlay Mueller’s actions.

That is, an equally brave Mueller with less support from an independent legislative branch might very well have failed. When it comes to a constitutional crisis, strength of character is hugely important, but it isn’t enough on its own.

From the time Trump was elected, it’s been clear the U.S. Constitution would undergo a stress test that would reveal its weak points. That test is ongoing. We still need to hear what is in Mueller’s report, and Congress needs to consider what action, if any, to take in response.

Today, we are at the beginning of the end, not the middle or end of the end.

Yet in the momentary lull before we find out more about the substance of the report, it’s worth taking the moment to celebrate the structures that enabled the report to be produced and completed. Our Constitution is by no means perfect, but it doesn’t have to be. When it comes to constitutions, like parents, good enough is good enough.

To contact the author of this story: Noah Feldman at nfeldman7@bloomberg.net

To contact the editor responsible for this story: Stacey Shick at sshick@bloomberg.net

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Noah Feldman is a Bloomberg Opinion columnist. He is a professor of law at Harvard University and was a clerk to U.S. Supreme Court Justice David Souter. His books include “The Three Lives of James Madison: Genius, Partisan, President.”

©2019 Bloomberg L.P.