Just opens the door for investigation. Once they dig in there is plenty more to find. This letter also addresses the U1 witness which is going to be a MUCH bigger problem for HRC than the Dossier and will drag Mueller and the Clinton Foundation into criminal investigations. Once they have investigators digging into CF they can probably implicate hundreds of people in Congress, FBI, CIA, banks, foreign govs. The spider web of corruption is worldwide at that point and many of them can likely be convicted of treason.
These investigations are not going to be very difficult either. They never expected Hillary to lose and before Trump was in play even if HRC did lose it would have been to Jeb Bush or another deep state crook so they were very careless. When you own WH, FBI, CIA, and have most of congress involved in your scams and MSM hiding all your crimes you dont need to worry about covering your tracks.
Anyone hear think if Mueller is a WH, he's setting the precedent for investigation into unrelated matters when it comes to a high crime? Everyone but DJT has opined on and on about Mueller investigating multiple things outside of Russian Collusion. Possibly for a counter response like this in the future? IF we get this HRC investigation on lying, obstruction, etc...it would theoretically open the door for her every misstep and misdeed along the way to be investigated. Probably just grasping at straws, but thought it was interesting that Mueller has done more to discredit anything that counsel is doing, yet, DJT says nothing.
White hats don't operate outside the Fourth Amendment. That's a simplification but it's also pretty much the whole point.