The Commission to Assess the Threat to the United States from Electromagnetic Pulse Attack has provided a compelling case for protecting civilian infrastructure against the effects of EMP and geomagnetic disturbances (GMD) caused by severe solar storms. Similar to protecting critical infrastructure against any hazard, it will be important to take a risk-based priority approach for these two electromagnetic threats, recognizing that it will be fiscally impracticable to protect everything. In this regard, EMP and GMD are particularly challenging in that they interfere with electrical and electronic data, control, transmission, and communication systems organic to nearly all critical infrastructures, simultaneously, over wide areas. The affected geographies may be continental in scale. These events thus represent a class of high-consequence disasters that is unique in coverage and ubiquitous system debilitation. Such disasters deserve particular attention with regard to preparedness and recovery since assistance from non-affected regions of the nation could be scarce or nonexistent. At first blush, the problem of where to begin in developing a national protection program seems overwhelming. Despite the challenges posed by such an endeavor, it is the purpose of the present work to suggest that such a program is possible and affordable based on a system risk-based priority approach.