The Mueller "investigation" was covering fire for Hillary and all those involved with Crossfire Hurricane and the Steele Dossier. Weissman's hope was to indict as many White House staff as possible for process crimes, a al Scooter Libby, the brass ring being a pretext for impeachment.
In the event Nasty Pelosi didn't even need a pretext for impeachment, a vague accusation was sufficient.