Which of the following is NOT a typical method employed by terrorist groups to achieve their goals?

Terrorist groups typically pursue aggressive and violent methods to further their objectives, often seeking to instill fear and gain attention for their causes. Among these methods, negotiation with political leaders is not commonly associated with terrorist tactics. While terrorist organizations may express a desire for certain political outcomes, they usually engage in violence and intimidation rather than lawful dialogue or negotiation. This sets the method of negotiation apart as it contrasts with the other options, which are all recognized techniques utilized by terrorists to exert pressure on their governments or to provoke mass fear and chaos.

Skyjacking and hostage-taking involve direct, violent actions that can create a high-profile platform for the terrorists' grievances, while attacks against security forces aim to weaken the state's ability to respond effectively. Covert operations are used to gather intelligence or conduct sabotage without detection, aligning with the goal of turmoil. Thus, negotiation does not reflect the common modus operandi of terrorist groups, making it the correct choice as the method not typically employed to achieve their goals.