Serious question: Even in a best-case scenario, there's no avoiding that foreign governments will have access to many of the nation's secrets and classified information. They probably always had spies embedded high up in the government already. I'll bet they have a clone of Trump's phone, access to Tulsi Gabbard's email, plus a lot of these people are incompetent, the FBI will be run by grifters, etc.
What is the end result of all this? How bad can it get in terms of national security? Remember, best case scenario here.