Who is described as a notable figure in the context of counterintelligence?

The notable figure in the context of counterintelligence is Robert Hanssen. His actions have had significant implications for U.S. national security. Hanssen is infamous for his betrayal as he was an FBI agent who spied for Soviet and later Russian intelligence services for over two decades. His espionage activities caused immense damage, compromising numerous intelligence operations and sources.

Understanding Hanssen's case is crucial in the field of counterintelligence because it highlights the vulnerabilities that even high-level officials may possess and the importance of personnel security measures. His actions led to substantial reforms within the FBI and other intelligence agencies. These reforms aimed at enhancing counterintelligence protocols and practices to prevent similar breaches in the future.

This context underscores why Hanssen is a figure of significant interest in discussions related to counterintelligence, as his case is often used as a cautionary tale about the risks associated with insider threats and the need for robust counterintelligence strategies.