Mueller has a very simple problem.
The only purpose of his investigation is to provide fodder for a possible Dem majority to impeach President Trump. His investigation is based on a conspiracy theory invented by the Clinton campaign and utilized for actual criminal eavesdropping by the Obama administration.
And there's nothing actually there. Worse still, Republicans are going on the offensive. They're peeling back the layers of collusion between the Clinton campaign and DOJ/FBI officials opposed to Trump. Fusion GPS, which was the interface between the two, is seriously sweating.
Meanwhile Mueller, the guy who put the Washington Post and CNN in the black, whose investigation keeps lefty hopes for overturning the election results alive, has to keep delivering something.
Unfortunately he's running out of material.
There's an old trouper's tradition, when you have to repeat, you're done. The threats to issue another indictment against Manafort, the juiciest of Mueller's pigeons, is sadly repetitive. It's the usual theater in which Mueller's Hillary Clinton supporters leak word of what he's going to do to friendly media outlets, but it's been done.
All this political theater is just that. Theater.
And theater is supposed to hold your attention. The permanent investigation is meant to help Dems win big in the coming year. And then have material that is not criminally actionable to use against Trump.
But Mueller is already in reruns.