Prevention of Terrorists attack
The prevention of any possible terrorist threats
Terrorists on the web
One of the many ways terrorists communicate is through the internet. If the U.S. had the authority to search through someones house because of a possible terrorist threat via messages on the internet there would be a decreased chance of any bombings like 9/11 or the Boston bombing.
How it would work
How it works is the government taps into any social websites like Facebook or Twitter, as well as messages and searches for keywords (that way you can still have your privacy) if any come up they will be read and determine if it's a possible terrorist threat.