As Westley said to Inigo in The Princess Bride … get ready for disappointment. Donald Trump vented on Twitter yesterday about House Democrats’ apparent plans to redo the entire Robert Mueller investigation, starting by calling Mueller himself to testify. While Trump might be able to do something about the redo, there won’t be much he can do to stop Mueller from testifying:

Trump’s frustration is legitimate, even if undisciplined. Later last night, Trump tweeted out that the investigation had “stolen two years of my (our) Presidency (Collusion Delusion) that we will never get back.” Given the complete goose egg Mueller found on collusion, that’s a fair point. Voters seem to agree, with polls mostly showing a large shift away from impeachment and Americans outside the Beltway talking about basically everything else but the Mueller report.

Unfortunately, whether Mueller testifies has little to do with the president. Trump can theoretically stop others in his White House from testifying by invoking executive privilege, a claim that preserves the president’s ability to get open and honest input from his advisers. The White House has already made clear that they plan an aggressive strategy for these claims, while House Democrats claim that Trump’s waiver of privilege for Mueller’s investigation negates those claims for all time. Chris Matthews offered a weird analogy to virginity last week in an interview with Kamala Harris, who, er, wasn’t enthusiastic about adopting it:

I’m no fan of Harris, but the look on her face was priceless — and perfect. Matthews later apologized for the metaphor, but it’s not far off from what Democrats are arguing. They may well prevail on that argument, but it will take months if not years before it gets settled by federal courts. In the meantime, no one will be testifying about their conversations with the president, which will stop the obstruction part of the Democrats’ redo in its tracks.

It’s tough to see how executive privilege would apply to Mueller, however. Trump famously declined to sit down with the special counsel at all, so Trump can’t claim to have engaged in any kind of advisory relationship with Mueller. Executive privilege doesn’t attain to everyone in the executive branch; it only attains to the president, and then to those interactions where the president receives advice and input. Absent that, Trump has no control over Mueller’s testimony or decision to appear before Congress. And since he is no longer special counsel and has no requirement to take direction from William Barr or Trump, Mueller can decide for himself to appear and to discuss what he sees as appropriate.

In the end, though, House Democrats will likely find Mueller’s testimony as disappointing as his report. Mueller is an institutionalist, someone who respects the norms of the Department of Justice no matter how much he might (or might not) resent Trump and Barr. It’s very unlikely that Mueller would provide any more information to Congress than what he included in his report; he likely felt that he reached the limits of prosecutorial transparency with that report already. House Intelligence chair Adam Schiff already started lowering the bar last week on Mueller’s potential testimony, and Lindsey Graham’s call on Democrats’ bluff over the Barr letter tells us he’s convinced Schiff’s right.

Mueller’s testimony will take place whether Trump likes it or not. Better to get it over with now, though, rather than drag this one out into 2020.