DHS Resilience Framework: Providing a Roadmap for the Department in Operational Resilience and Readiness [open pdf - 4MB]
From the Executive Summary: "Since May 1998, Presidential and Federal Directives and Executive Orders have been issued on protecting national critical infrastructure. Critical infrastructure are those assets and systems that are so vital to the United States that the incapacity or destruction of them would have a debilitating impact on security, national economic security, national public health, or safety. Since Hurricane Katrina in 2005, there has been a notable shift in emphasis from protecting critical infrastructure but to also ensuring that communities and Federal agency infrastructure are resilient. Simply stated, resilience is the ability to adapt to changing conditions and withstand and rapidly recover from disruption. Hazards and threats that can cause disruptions can take many forms, including natural, technological, and human caused. These could entail, for example, severe weather, power outages, roadway failures, acts of terror, and cyberattacks."
U.S. Department of Homeland Security: https://www.dhs.gov/