The document outlined the de facto national security strategy of the United States for that time (though it was not an official NSS in the form we know today) and analyzed the capabilities of the Soviet Union and of the United States of America from military, economic, political, and psychological standpoints.
This document is critical to an understanding of the Cold War, its legacy on similar national security documents, such as the National Security Strategy March 2005, also provides insight on current US foreign policy. The implementation of NSC-68, although the proposal was initially refused, shows to what extent it marked a 'shift' in US policy not only towards the USSR but indeed all other communist governments. The signing of the document showed the clear defined and coherent US policy that to some extent did not exist until 1950 under the Truman administration. Furthermore, it can be argued that this document proposed by the security council solved Truman's problem from attack from the American right just after the 'reds in the beds' scare and the Alger Hiss case. Although not made public, it did show up on the surface as an increase in both conventional and nuclear capabilities of the USA, and indeed provided the USA with a greater financial burden.
Original document here.