Strategic defence is a type of military planning doctrine and a set defense and/or combat activities used for the purpose of deterring, resisting, and repelling a strategic offensive, conducted as either a territorial or airspace, invasion or attack; or as part of a cyberspace attack in cyberwarfare; or a naval offensive to interrupt shipping lane traffic as a form of economic warfare.
In fact, it often involves military deception, propaganda and psychological warfare, as well as pre-emptive strategies.
In military theory, strategic defense thinking seeks to understand and appreciate the theoretical and historical background to any given war or conflict scenario facing the decision-makers at the highest level.
Although national military intelligence services are always conducting operations to discover offensive threats to security to ensure adequate warning is provided to bring defense forces to a state of combat readiness.
In terms of combat scale, a strategic defensive is considered a war that can last from days to generations[1] or a military campaign as a phase of the war, involving a series of operations delimited by time and space and with specific major achievable goal allocated to a defined part of the available armed force.