National Conference of State Legislatures:

Electronic surveillance is also examined in a brief
that is part of NCSL’s series, “States
Respond to Terrorism,” which surveys states’ efforts to protect democracy
from future terrorist attacks.

Electronic Surveillance involves the traditional laws on wiretapping–any
interception of a telephone transmission by accessing the telephone signal
itself–and eavesdropping–listening in on conversations without the consent
of the parties.

Following the tragedies of September 11, there is growing
support to give law enforcement agencies more power to tap into private
communications to thwart further acts of terrorism by monitoring private
electronic communications. State and federal policymakers face the challenge
of balancing security needs via electronic surveillance against the potential
erosion of individual privacy.