The stunning revelation by longtime operative Donna Brazile that the Hillary Clinton campaign secretly took control — literal control — of the Democratic National Committee a year before Hillary became the party’s nominee is the talk of American politics.

As it should be.

Brazile’s piece in Politico describes her shock at the discovery of formal legal paperwork between the two entities when she took the reins at the DNC in August 2016. Brazile had been tapped for the job when DNC chair Debbie Wasserman Schultz was forced to resign. Leaked emails had shown how Schultz had been putting her finger on the scale to help Clinton while the insurgent Bernie Sanders campaign was making a serious bid to seize the party nomination away from New York’s favorite carpetbagger.

Her account features ridiculous and unbelievable melodramatics — she says she “gasped” when she found out the truth and that she “lit a candle in my living room and put on some gospel music” to calm her before she called Sanders to deliver the awful news.

But silly though Brazile’s prose is, her account is vitally important not only for all those who want to understand how American politics works but also for the future of Brazile’s beloved party.

First, it raises key questions about what was happening as Clinton faced a time of trial in the middle of 2015. Her reputation was taking hits as her evasions and denials and untruths about what had happened to the private email server she had set up illegitimately in 2009 seemed to mushroom on a daily basis.

As this was happening, she found herself with only two semi-serious challengers for the nomination — Sanders and former Maryland Gov. Martin O’Malley.

There was another person out there — then-Vice President Joe Biden. Though grieving over the tragic loss of his son Beau, Biden was still seriously considering a late entry into the race. Indeed, it would not be until October that Biden would declare himself out of contention.

Consider, then, that a formal agreement signed by the DNC and the Clinton campaign was executed in August 2015, two months before Biden made his decision.

The agreement, according to Brazile, “specified that in exchange for raising money and investing in the DNC, Hillary would control the party’s finances, strategy and all the money raised. Her campaign had the right of refusal of who would be the party communications director, and it would make final decisions on all the other staff. The DNC also was required to consult with the campaign about all other staffing, budgeting, data, analytics and mailings.”

Forget for a moment the unfairness to Sanders that would characterize the next year as he surged against Clinton. What role might this agreement have played in Biden’s decision-making? Did he know? Did Hillary tell him? Did President Barack Obama tell him? Did Biden realize he would be fighting not only Clinton but the entire apparatus of his own party and decide to bag it?

Brazile has done her party a service because this honest account of the maneuverings of the Clinton campaign is a necessary step for Democrats in determining how to gauge their own organizational and ideological health.

This is long overdue. Rather than try to figure out how they contributed themselves to their calamitous 2016 fate, they have spent a year indulging the fantasy that they really won the election and had it stolen from them.

Stolen by Russian ads on Facebook. Stolen by “collusion,” whatever that might be. Stolen by racism. In other words, they were robbed and the only thing that matters now is catching and jailing the robber.

Sorry, fellas. The 2016 election was the culmination, not the beginning, of a Democratic implosion.

Over the previous six years, Democrats had lost 60-plus House seats, nine Senate seats, 14 governorships and 1,000 state and local offices. Russians didn’t do that. Democrats did — with the help of a surging Republican Party that found itself after election night in its strongest electoral position across the country since 1928.

Democrats need to understand their own role in their own rotting position — including how they sold themselves to the Clintons for a mess of pottage they never even got to eat — if they are to have any hope of reversing the Republican tide.

Even if their fantasies were made flesh today and Donald Trump were somehow banished from Washington, the Democratic Party would be in no stronger institutional shape than it was yesterday.

Donna Brazile has given her unwilling fellow party members a good, long, unwelcome look in the mirror. Let’s see what they do with it.