Barack Obama is very careful about some things. He makes sure his political allies know that his legacy has to be protected. As a result, the bits of information we get about the Obamas and their post-White House adventures are limited and usually cast in a very respectable-elder-statesman fashion.

People who worked for the former president do not go out and create any sort of drama related to what happened while they were in power. They defend him and his accomplishments, and they attack anyone who questions it — and their behavior is often endorsed by friendly reporters and pundits throughout the media.

So, when a POLITICO Magazine piece comes along and attacks his Vice President, Joe Biden, as incompetent and a joke, and the quotes are all coming from former Obama staff and aides, you know that this is deliberate. There is a reason this piece and these attacks see the light of day: Because Obama wants them to.

As my colleague Mike Miller put it, the team-up of Biden and Obama in 2008 was clearly a case of “strange bedfellows,” and it becomes clear that Obama wasn’t so much a fan of Biden as he needed someone who would be both an experienced Washington veteran and a sycophant. Based on how the relationship worked out, it’s clear he couldn’t have made a better choice.

So, what gives with this piece, which includes such gems as “Young White House aides frequently mocked Biden’s gaffes and lack of discipline in comparison to the almost clerical Obama” and “Obama had begun embracing Clinton as a possible successor years before Biden lost his son, while the vice president was laying the groundwork for his own campaign”? Why would all this come out right now? The story dropped on August 14 — three days before the DNC digital convention started, when Biden would be coronated as the next de facto head of his party.

Biden was chosen to be his running mate as a way to negotiate the political chaos caused by his challenge to (and, ultimately, victory against) Hillary Clinton. By picking an established member of the party’s elite, Obama brought to his side a party that was unsure of young, risky upstarts (this same party, which sees him as an elder statesman and not an upstart, casts the same doubt on politicians like Alexandria Ocasio-Cortez, and now he appears to have snubbed her when he released his list of endorsements weeks ago).

That spurred his own political revolution, where he went from upstart to establishment. He is the gold standard Democrat to whom progressives and journalists compare Trump and other Republicans. His legacy as a president and as a statesman is now fully established, and that legacy is very important to him.

But, if he and his allies felt this way about Biden, why wait until now to speak out about it? Kamala Harris.

It’s clear the Obama faction of the Democratic Party wanted Susan Rice to be Biden’s running mate. That would allow her to run as Biden’s successor and continue to ensure that Obama’s legacy as a president stays intact. Harris is, basically, an unknown quantity because she has no core beliefs of her own. Karen Bass would have been Pelosi’s puppet in the Biden administration. The other candidates did not have a record of loyalty to Obama, and at a time when Trump has worked to undo as much of Obama’s record as possible, the Obama camp needed someone in the next Democratic administration to be his legacy’s savior.

Prior to this, the Obama camp had been solidly in Biden’s corner, because none of the other presidential candidates were people who could be relied on to protect that legacy. Bernie Sanders’ wing of the primary wanted to erase it all and start over. Other candidates were various shades of progressivism but were set on doing their own thing, rather than building on his record. Biden, who ran as Obama’s guy and won the primary thanks, in large part. to attacks on him being seen as attacks on Obama, was the only choice.

But now, because Biden is trying to be his own man, that puts the legacy at risk. Because Biden did not do what Obama’s allies were wanting him to do, they are now free to go out and establish this divide between Biden and Obama so that the latter can wash his hands of whatever Biden ends up doing.

Barack and Michelle themselves will naturally have nothing but praise for Biden, but it’s fairly obvious by now that they always saw Clinton as their heir and not Biden.