At times, sacrifices need to be made for the greater good. For example, in response to the 9/11 terrorist attacks, the United States government modified Constitutional rights in order to increase national security and reduce the risk of terrorism on American soil. Such precautions have taken various forms. One of which has been an increase in both targeted and random screenings of airline passengers. Although such screening violate individual rights to privacy, it is in the name of security and is ultimately necessary. 
This is no different in the case of mandatory national conscription. More specifically, we must sacrifice some of our own civil liberties for security and prosperity. Citizens of the United States should stop thinking so individualistically and start looking at the bigger picture, one of collectivism.