Critical infrastructure describes the physical and cyber systems and assets that are so vital to the United States that their incapacity or destruction would have a debilitating impact on our physical or economic security or public health or safety.  The nation's critical infrastructure provides the essential services that underpin American society.

The Acting Secretary of Homeland Security issued a National Terrorism Advisory System (NTAS) Bulletin, subsequently extended by the Secretary of Homeland Security, due to a heightened threat environment across the United States, which DHS believes will persist in the weeks following the successful Presidential Inauguration.  Information suggests that some ideologically-motivated violent extremists with objections to the exercise of governmental authority and the presidential transition, as well as other perceived grievances fueled by false narratives, could continue to mobilize to incite or commit violence.