完全合法

A security clearance is granted to an individual and generally recognizes a maximum level of clearance. Exceptions include levels above compartmentalized access or when an individual is cleared for a certain type of data. The President of the United States may be given access to any government or military information that they request if there is a proper "need to know", even if they would not otherwise be able to normally obtain a security clearance were they not the President.

摘自维基百科