The electrical grid in the United States is increasingly exposed to risks from physical, cyber, infrastructure, and demand-side disturbances, which calls for a thorough evaluation of its weaknesses to guarantee resilience and dependability. This systematic literature review consolidates current studies to pinpoint essential gaps and developing patterns in grid security, with particular attention to aspects such as cyber-physical system security, smart grid obstacles, electric vehicle adoption, and data-driven countermeasure approaches. We examine a wide range of academic studies to assess the interaction among technological, economic, and policy elements influencing grid resilience, thus delivering a comprehensive grasp of existing weaknesses and possible solutions. The review indicates cyber threats, especially those aimed at industrial control systems, continue to be a primary concern, whereas the increasing adoption of distributed energy resources and electric vehicles introduces new risks on the demand side. The deterioration of infrastructure and its interconnected nature worsen systemic vulnerabilities, underscoring the necessity for flexible policies and sophisticated analytical methods. Our results highlight the necessity of adopting interdisciplinary methods to tackle these issues, with a focus on economic motivators, policy structures, and novel technological solutions to improve grid protection. The study ends with practical recommendations for researchers, policymakers, and industry stakeholders, urging the adoption of forward-looking strategies to strengthen the grid against changing risks while maintaining a balance between sustainability and operational effectiveness.