@izzythepush,
This is not "desperation," it is basic constitutional law. Any person can "consent" to a search of their own property, but they CAN'T give valid consent to search someone else's property.
A landlord, who owns the real property, cannot, for example, authorize the police to search premises which he "owns," but which he has rented to another. Consent from the tenant would be required. Either that, or a warrant. Otherwise there would be a 4th amendment violation.
Mueller's office is trying to play games by claiming the GSA gave "valid" consent. But the GSA would not have the authority to give valid consent. They "let" (rented) their offices and equipment to Trump's transition team, but they did NOT "own" their work product, attorney-client communications, private correspondence, etc., even if it was placed on equipment which they "owned." The were not the "account owner" for search purposes, as Mueller claims (disingenuously).