In the hands of competent and well-trained crews, modern long-range SAMs such as the S-400 can inflict significant damage on an adversary. Their ranges allow them to target key enemy enabler aircraft, such as valuable aerial refueling tankers and airborne early warning and control aircraft. Their flexible targeting capabilities mean they can defend against multiple different types of threats and attacks. And their — albeit limited — anti-stealth capabilities offer the potential to bring down some of the best combat aircraft currently in operation.

The Limitations of SAM Capabilities

Yet, even with these impressive theoretical capabilities, modern long-range SAMs such as the S-400 are only as good as the context within which they exist; that is, the systems can be more or less effective depending on the type of adversary they face. An S-400, for instance, could be a formidable threat to a limited enemy incursion, but even a full S-400 battalion only has around eight missile launchers, typically with four missiles each. 32 missiles are certainly enough to cause serious harm to a limited attack. But if an S-400 battalion is acting in isolation or is not backed up by other modern air defenses, it likely doesn't have enough missiles to withstand a determined onslaught. This is especially true in the Middle East, where numerous customers deploy expensive systems in batteries rather than battalions — a battery being the smallest unit composition — meaning they might only have 16 total missiles at the ready.

And despite their impressive theoretical reach — the advanced Russian 40N6E missile has a supposed range of 400 kilometers (250 miles) — long-range SAMs like the S-400 are still vulnerable to standoff missile attacks. Furthermore, geographical factors weigh heavily on a system's usefulness, with mountainous features able to block the systems' sensors. A low-flying target can take advantage of geographical features and the curvature of the earth to avoid an S-400 interception for far longer than a high-flying target. So, against a low-flying cruise missile, an S-400 will more likely find success at a distance in the tens of kilometers rather than in the hundreds. Ultimately, an isolated S-400 battery or even battalion will, therefore, be vulnerable to a saturation standoff attack and may even be destroyed without destroying a single enemy aircraft.

Designed to Be Team Players

These factors reinforce a key fact about SAM systems like the S-300 and the S-400, which is that they were never designed to operate as stand-alone systems and are most effective as part of a much wider integrated air defense system (IADS). An effective IADS consists of layers of different types of SAMs — from the very short range to the very long range. It also incorporates many different radars and other sensors for the detection of different types of enemy targets. The larger (in geographic scope), the denser (in terms of numbers of different systems within) and the more technologically advanced the IADS, the greater its ability to protect a given airspace.