The Underperformance of U.S. Air Defences; How it Affects Strategic Decision Making and Reduces Chances of War on the Korean Peninsula

In January 2018 the U.S. military tested its Aegis Ashore land based ballistic missile defence system off the Hawaiian coast. The military launched an SM-3 missile to intercept a mock incoming missile, but failed to intercept the target. The test came amid escalated efforts by the U.S. military to increase and modernise its missile defence deployments, and the country today seeks to develop a three stage system for the mainland comprised of THAAD, the Aegis Ashore and the Patriot to protect its territory against missile attacks. The U.S. Missile Defense Agency reported that "sailors manning the Aegis Ashore Missile Defense Test Complex conducted a live-fire missile flight test using a Standard Missile-3 (SM-3) Block IIA missile launched from the Pacific Missile Range Facility, Kauai, Hawaii, Wednesday morning." The agency did not specify the test's results, though it later emerged that it had ended in failure.

The failure of the SM-3 comes in the wake of a previous failed test in July 2017, and shows that the Aegis system remains far from operationally ready. The failed test came just weeks after the failure of the Patriot, supposedly the most reliable of U.S. missile defence systems and the only one having undergone combat testing, to intercept an extremely basic Yemeni missile fired by Yemen's Ansurallah coalition forces over Saudi airspace. Whether the United States will be able to develop more reliable missile defence systems in future remains to be seen, but the country has been struggling with the poor reliabilty of its systems for several decades ever since the Gulf War of 1991. Several U.S. experts in the field of missile defence have noted that prospects for the country developing a capable and reliable missile defence system are highly unlikely, with renowned expert Theodore Postol stating in 2016 following a series of failed tests: “I think basic physics would tell you that this system no only doesn’t work, but it will never be able to work. So, this is nothing to do with engineering technology, it has to do with the order to tell the difference between decoys and warheads. This is a fundamental problem with the system." The New York Times and several other leading U.S. publications have published articles to the same effect, with the Times noting in March 2017: "the $300 billion spent since the Eisenhower era on traditional antimissile systems, often compared to ‘hitting a bullet with a bullet,’ had failed the core purpose of protecting the continental United States. Flight tests of interceptors based in Alaska and California had an overall failure rate of 56 percent, under near-perfect conditions. Privately, many experts warned the system would fare worse in real combat.”

The United States' failed missile interception tests come in the wake of high tensions with North Korea, a country which has pledged to target the U.S. mainland and facilities on Guam and Hawaii in retaliation if attacked. North Korea has made significant progress in its nuclear and missile programs, and upon inducting new modern systems such as the Hwasong-12, Hwasong-14 and Hwasong-15 and miniaturising nuclear warheads including hydrogen bombs, the country's retaliatory strike capabilities can pose a major threat to the U.S. mainland and a highly capable deterrent. While reports state that the United States is considering a 'bloody nose' limited strike on the country, the unreliability of the American missile defence systems and a lack of intelligence on Pyongyang's missile capabilities make such action extremely risky and therefore unlikely. Ultimately the U.S. cannot rely on its air defences to protect its airspace, and North Korean offensive capabilities are regardless advancing far faster than American defensive capabilities and are set to continue to do so in future. Missiles will grow in number and sophistication, the Korean satellite program will facilitate more accurate strikes, and nuclear payloads will become larger while warheads become lighter - making multiple warhead reentry vehicles a possibility in future. As a result chances of military action will only decrease as the vulnerability of U.S. territories increases with time. As the 40th President of the United States, Ronald Reagan, stated during his tenure "war begins when governments believe the price of aggression is cheap." The United States' apparent inability to defend its airspace from North Korean nuclear retaliation has made the price of any attack on the country intolerably high, and makes prospects for military action against the country far less likely.