Which mission from the Quadrennial Homeland Security Review Report addresses preventing an attack by sea?

The mission that addresses preventing an attack by sea is related to securing and managing our borders. This mission encompasses a broad range of activities aimed at protecting the integrity of U.S. borders, which includes preventing illicit activities, such as maritime terrorism or the smuggling of dangerous materials by sea.

The focus on maritime security is essential because the vast coastlines of the United States present unique vulnerabilities. Thus, securing these borders involves not only physical patrols and inspections but also the use of technology and intelligence to detect and deter potential threats that may come via the sea.

The other missions, while critical in their own right, do not specifically focus on the maritime aspect of border security. Preventing terrorism is broadly aimed at all forms of terrorist threats, emergency preparedness relates to responses to crises, and cybersecurity targets threats in the digital realm rather than physical attacks by sea.