President nixon sought to suppress publication of pentagon papers because they provided a secret history of

The publications revealed critical secrets of USA government deception to take the country to war.
 It revealed the existence of left wing radicals who influenced government decisions who would go to any length to take the country to war at any cost. Nixon saw the confirmation of the Doves concerns regarding the war as critical to the survival of his administration,noting he had also pursued his own interests in the Vietnam.

Because broadest terms allows the law flexibility depending on changing society and circumstances.