Defensive strategies for dealing with cruise missile threats fall broadly into two categories, the first being the denial or deterrence of launch and counterforce strategies, the second being the interception of launched weapons.
Deterrence strategies amount to threatening credible retaliation, regardless of weapons used.
Counterforce strategies amount to pre-emptive destruction of the opponent's cruise missile capability before it can be deployed or launched. This approach requires similar capabilities to deterrence, but involves much more specific targeting.
Denial of launch strategies amount to shooting the archer, not the arrow paraphrasing the 1980s US Maritime Strategy. This involves killing cruise missile carrying aircraft, sinking cruise missile armed ships/subs, or destroying ground mobile TELs before they have the opportunity to fire. This approach also requires a robust force structure, including good maritime and land strike capabilities, good air defence capabilities, and good ASW capabilities.
Interception of launched cruise missiles presents its own challenges, especially in terms of fighter persistence, speed, missile payload, radar performance, tanker and AEW&C numbers. However, in strategic terms it is often the only option left, especially during the period preceding an outbreak of full scale hostilities. As cruise missiles present an attractive first strike weapon to disrupt air defence infrastructure, their use is most likely in the opening round of a conflict.
To implement either deterrent or direct counterforce strategies to defeat an opposing cruise missile force requires significant targeting and strike capability. This strategy requires that a opposing force armed with cruise missiles be attacked and destroyed in situ, for instance by demolishing airfields, launch aircraft and missile stocks on the ground, or by analogous strikes against naval bases hosting cruise missile armed warships or submarines.
Targeting, with the exception of ground mobile TELs, is less challenging as airfields and naval bases are large fixed infrastructure which can be effectively surveilled using satellites or human intelligence assets, although timeliness can be an issue if signs of strike preparation are the trigger for a pre-emptive attack. Cruise missile warfare like ballistic missile warfare to a large extent obeys the use them or lose them rule, and there are strong incentives to fire off as much of the war stock as early as possible in a campaign.
Interdicting cruise missile armed submarines, or intercepting cruise missile carrying aircraft, also present interesting challenges. However, while a riskier strategy than counterforce strikes in situ, interdiction/interception achieves a similar effect by inflicting cumulative attrition on the opponent's delivery force. Rather than destroying the force in a small number of concurrent or closely timed strikes, the attrition occurs overs days or weeks as the opponent's assets are ground down to impotence. In political terms counterforce strikes, especially if pre-emptive, are problematic, but interdiction/interception of delivery platforms presents a clear cut case of defensive action with clear hostile intent by an opponent. The risk is that not every opposing platform is stopped before it launches, and that many will escape to attack yet again.
When interdiction of a submarine or interception of a strike aircraft fails, and cruise missiles are launched, the default strategy is then to engage and destroy these before they reach their targets.
In practice any model for defeating a cruise missile armed opponent must be multi-layered, even if the counterforce strike option is not implementable due to inadequate strike capabilities. Launch platforms must be detected, tracked and engaged, and if this fails, the cruise missiles must be detected, tracked and engaged. The air-sea gap is valuable in this respect, as it provides a defacto free-fire zone for fighters tasked with cruise missile intercepts, and the distances involved provide for repeat engagement opportunities, fighter fuel and weapon payloads permitting.
Reliance on land based SAM systems for terminal defence of target areas is a popular but relatively ineffective strategy, as high performance SAMs with expensive high power-aperture radars are required, and even with mast mounted antennas to improve coverage the footprint is bounded by ranges of miles to at most tens of miles. Placing SAM batteries on warships increases this expense for some gain in mobility.
