Update: In case there was any doubt about whether he would shift course and go hard after the DNC, Bernie Sanders made clear in a speech Monday to delegates that they should focus on electing Clinton. "We have got to elect Hillary Clinton and Tim Kaine," Sanders said to some boos. In response to the boos, he said, "This is the real world that we live in."

Sen. Bernie Sanders was booed and jeered by his own supporters after he said, "We have got to elect Hillary Clinton and Tim Kaine," while speaking at the Democratic National Convention on July 25. (Video: Reuters/Photo: Ricky Carioti/TWP)

Bernie Sanders has long argued that the Democratic National Committee was out to get him. And now, a trove of internal DNC emails released by WikiLeaks appears to back up elements of that assertion.

There are multiple instances of DNC staffers appearing to conspire against Sanders, along with evidence that they viewed him and his campaign with some degree of scorn and even apparently coordinated with a Clinton attorney in one case.

But on Sunday, Sanders's response was muted.

"I mean, there's no question to my mind and I think no question to any objective observer's mind that the DNC was supporting Hillary Clinton, was in opposition to our campaign," Sanders said on CNN's "State of the Union." "So, I'm not quite shocked by this. And that is why many, many months ago, I made it clear that I thought Debbie Wasserman Schultz should resign, should step down." (Wasserman Schultz did step down later Sunday.)

Rather than gloat, Sanders didn't seem to want to re-litigate the whole episode. In fact, he did what any good soldier for the Democratic Party and Clinton would do: refocused things on electing Clinton and defeating Donald Trump.

Host Jake Tapper, apparently a little surprised by Sanders's response, gave him another crack to respond to perhaps the most offensive email — one in which a DNC staffer suggested raising questions about whether Sanders was an atheist. Sanders said it was an "outrage," but then he quickly pivoted to Clinton vs. Trump.

"I think the focus, though, that I am going to go forward on right now is to make sure that Donald Trump, perhaps the worst Republican candidate in the modern history of this country — somebody by temperament, somebody by ideology must not become president of the United States," Sanders said. "I'm going to do everything I can to defeat him, to elect Hillary Clinton, and to keep focusing, keep focusing on the real issues facing the American people."

What's going on here? Here is a guy who spent months arguing that the Democratic primary process was rigged against him. He has finally got some proof, and he just wants to move on?

Trump noticed the apparent incongruence and has decided to troll Sanders on Twitter, suggesting that he has lost the will to fight and has effectively been neutered.

Trump is poking the bear here for a reason: He would love to see Sanders and his supporters lash out at Clinton and make a mess of the Democratic National Convention — much like his supporters did when they booed Wasserman Schultz loudly at a Florida delegation meeting on Monday morning.

But that's also a big part of the reason that Sanders can't take the bait.

However tempting it might be for Sanders to rail against the content of the DNC's leaked emails — programming note: he speaks at the convention Monday night! — Sanders is now a Clinton supporter, and this DNC email issue is something that threatens to hurt Clinton.

In endorsing Clinton, Sanders made a calculated decision to work within the Democratic Party system to effect the change he wants to see in the party. He has already got the DNC to move its platform to the left and to reexamine the use of superdelegates — which he argued were undemocratic and part of a rigged system.

And then there's this: While some of the content of the emails is pretty damning, almost all of them came late in the primary process — when Clinton was clearly on track to win and Sanders's odds were looking longer and longer. Basically, all of them are from late April or May, when the delegate math was prohibitive for Sanders.

In other words, although it certainly looks as if DNC staff engaged in some shenanigans, it would be pretty hard for Sanders to make the argument that this kind of bias would have changed the result of the Democratic contest. Trump and Republicans would love for Sanders to press the idea that Clinton's win wasn't legitimate — and some Sanders backers are pushing for a roll call vote — but the evidence just isn't there, and Sanders knows it.

And even if it were, Sanders would be engaging in a highly unlikely effort to throw the results into question — an effort that would probably only accrue to Trump's benefit. Even if the system was/is rigged, un-rigging it at this stage would be a massive undertaking.

But it is still fascinating to see Sanders presented with this information at perhaps the most inopportune time. Imagine if this had happened during the primary season.