"(2) monitoring persons suspected of endangering national security" was something that the federal government did in <span>response to Cold War tensions after World War II and again in response to the September 11, 2001,
terrorist attacks.</span>
Hope this helps:
https://www.google.com/url?sa=t&source=web&rct=j&url=http://thehermitage.com/learn/andrew-jackson/general/war-hero/&ved=0ahUKEwiZjt6U0PnTAhXG7iYKHT4gBAsQFggfMAA&usg=AFQjCNG-keoioPWqUOBY6IOeiEJo1AXj0w