High Altitude Electromagnetic Pulse (HEMP) and High Power Microwave (HPM) Devices: Threat Assessments [Updated March 26, 2008] [open pdf - 164KB]
"The threat of an EMP attack against the United States is hard to assess, but some observers indicate that it is growing along with worldwide access to newer technologies and the proliferation of nuclear weapons. Policy issues raised by this threat include (1) what is the United States doing to protect civilian critical infrastructure systems against the threat of EMP, (2) how does the vulnerability of U.S. civilian and military electronics to EMP attack encourage other nations to develop or acquire nuclear weapons, and (3) how likely are terrorist organizations to launch a smaller-scale EMP attack against the United States? This report will be updated as events warrant."
CRS Report for Congress, RL32544
Federation of American Scientists: http://www.fas.org/