Election processes are a crucial function to support the health and strength of a democracy. With the recent rise in the propagation of misinformation and disinformation both in the United States and worldwide, it is more critical than ever that we establish and maintain public trust in democratic election processes. This paper presents and examines current threats to U.S. elections and voting equipment. We provide an inventory of current literature centered around cyber, physical, and insider threats to and vulnerabilities in U.S. voting systems. This inventory is one of the first to comprehensively expand beyond the 2009 Election Assistance Commission (EAC) attack tree, which has long served as a foundational framework for understanding the potential vulnerabilities within U.S. election systems. In addition to identifying, categorizing, and discussing these threats and vulnerabilities, we also conduct a thorough review of proposed voting processes based on cryptography and distributed ledger technologies. This includes examining current implementation status and challenges associated with potential adoption, as well as the feasibility and effectiveness of these solutions. By providing an in-depth analysis of current election threats, vulnerabilities, and proposed solutions, this paper offers valuable insights into ongoing and future efforts to secure U.S. elections. It also highlights areas where further research, technology innovation, and conceptual design are needed to ensure that election systems can withstand emerging threats while maintaining trust in democratic processes.