One could argue the only way for the world to fully appreciate how corrupt Mr. and Mrs. are (in some instances they were a combination) is for the corruption to be revealed via prosecution.
In the interim, IMO, no president, Obama and Trump included should pardon anyone who may be charged with, or convicted of, national security breaches. Such a crime is against every man, woman and child in our country. In that regard, Comey laid out the basis of a compelling opening statement.