While the U.S. Navy might dominate the world’s oceans, there is one threat I continue to hear chatter about time and time again that keeps American sailors and senior officials up late into the night: the growing threat from cruise and now ballistic missiles that could deliver “mission kills” against U.S. vessels--especially aircraft carriers.

The challenge is well known and decades in the making. Nations like China, Russia and many others are investing serious resources in developing various types of missile-based systems to challenge the dominance of American seapower. The posterchild of such systems: the now famous (or infamous) Chinese DF-21D anti-ship ballistic missile (ASBM), of what many refer to as the “carrier-killer”.

While such threats may be proliferating across the globe, U.S. sailors and military personnel did get some welcomed news recently.

In what is being called a “a first-of-its-kind test”  the U.S. Navy launched a Standard Missile-6, or SM-6,  intercepting and then destroying a short-range ballistic missile at sea. Why does this matter? The test proved that “a modified SM-6 can eliminate threat ballistic missiles in their final seconds of flight.”

"SM-6 is the only missile in the world that can do both anti-air warfare and ballistic missile defense from sea," explained Dr. Taylor W. Lawrence, president of Raytheon Missile Systems, in a press release on Raytheon’s website. "U.S. Navy commanders want both capability and flexibility to meet a wide variety of missions, and that's exactly what SM-6 offers."

The press release also notes that “[the U.S. Missile Defense Agency’s] Sea-Based Terminal (SBT) program will protect against ballistic threats in their terminal phase of flight using SM-6 missiles integrated into the Aegis Weapon System. Called SM-6 Dual 1, it's on track to achieve initial operating capability in 2016.”

This is certainly all good news for the U.S. Navy. As threats grow from cruise and now ballistic missiles fired from multiple different domains (land, air or sea) U.S. and allied ships can use all the protection they can get.

However, long-term trends suggest the advantage in naval warfare is slowly creeping towards the “shooter” of the missile as opposed to the “defender,”in this case the naval vessel. As I explained back several years ago in The Diplomat:

“Think about it — could we someday see a scenario where American forces at sea with a fixed amount of defensive countermeasures (think SM-2s, 3s and 6s) facing an enemy with large numbers of cruise and ballistic weapons that have the potential to simply overwhelm them? Could a potential adversary fire off older weapons that are not as accurate, causing a defensive response that exhausts all available missile interceptors so more advanced weapons with better accuracy can deliver the crushing blow?”

The above for, at least for me, is the fundamental challenge for missile defense at sea. Now, you may ask: “why not just build more missile defense platforms?” While certainly possible, building more interceptors along with the launchers and systems to power them would be very expensive, especially compared to the much lower price points of the missiles they are trying to protect against.  Nations like China and Russia, seeing America building up its missile defense platforms, could very well build many more missiles, at very low price points, comparatively speaking.

This is a challenge for U.S. and other allied navies that will get more interesting in the months and years to come. Stay tuned.

For more information about the SM-6 and its capabilities, see the video below: 

Harry J. Kazianis serves as Executive Editor of the National Interest and as a Senior Fellow for Defense Policy at The Center for the National Interest. You can follow him on Twitter: @Grecianformula.

Image: Raytheon.