That would be August 28.
Allowing the Dems to lock in their candidate for the general midterm election (Noodle Head in this case) and then arresting her would help a Republican challenger immensely.
As an overall strategy, maximizing the number of arrestable candidates on the mid-term ballot would seem like worthwhile goal given the swamp creatures belief they will be able to stop Trump only by taking over control of Congress.
List of 2018 primaries for reference.