The Case for Aegis at Home

The National Defense Authorization Act (NDAA) 2017, signed into law by President Obama shortly before his departure from office, contained provisions which mandated a review of U.S. missile defense strategy. In support of this, President Trump subsequently ordered a Ballistic Missile Defense Review as a route to “strengthening missile-defense capabilities, rebalancing homeland and theater defense priorities, and highlighting priority funding areas." The report, which is required by Congress to also contain an analysis of the defense of the U.S. mainland against cruise missiles, is due to be delivered by the close of 2017.

These developments subsequently drew renewed focus to the U.S.’ existing missile defense systems. Since the dawn of the year, the U.S. Army has deployed THAAD launchers to South Korea, the Navy has successfully tested a new version of the SM-3 missile, and even the much-maligned Ground-Based Midcourse Defense (GMD) system has managed to hit something. But for all the progress that has been made over the last two decades, there is a realization that there can be no let-up in the pace of innovation and fielding.

Significant attempts have been made to improve U.S. defenses against cruise missiles, but they have met with limited success. Notably, the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS) – built around tethered aerostats fitted with surveillance systems – was developed to support fighters and missile batteries in shooting down cruise missiles. However, after billions being spent, the program was canceled after technical problems and the embarrassing escape of one of the aerostats in 2015.

What is needed from the Ballistic Missile Defence Review is a study which identifies future threats and outlines measures to address them in a realistic timescale and budget. However, given the tendencies of the Trump administration, there is a risk that there will be a focus on grandiose schemes over pragmatic solutions. Notably, both Congress and commentators have sought to emphasize the role of space-based interception systems.

Instead of a Reaganesque Star Wars (Strategic Defense Initiative) approach, the priority should be to build on existing systems without requiring disproportionate leaps. Part of this strategy should be what might be termed ‘Aegis at Home.' Based on an evolved version of Aegis Ashore, one of which is already operational in Romania with a second under construction in Poland, it would be designed to provide area and point defense against ballistic and cruise missiles. Congress itself appears open to an Aegis at Home-type approach: the NDAA 2017 contains a requirement that the Department of Defense produce an evaluation of options for “deploying one or more Aegis Ashore sites and Aegis Ashore components for the ballistic and cruise missile defense of the continental United States.” There have also been calls to make the Aegis Ashore test site in Hawaii operational to defend the islands.

Aegis at Home would be centered upon an AEGIS Ashore system fitted with the latest AN/SPY-6 radar and an expanded number of missile silos. An operational date of 2024 would allow time for the development of the SM-3 anti-ballistic missile’s capabilities to include an interim anti-ICBM function and the fielding of a revised JLENS system to track cruise missiles. The kinetic anti-cruise missile capability would rest with the SM-6 missile, with the ESSM acting as a point-defense backup. In time, fuller anti-ICBM engagement would be made possible through further evolution of the SM-3. Initially, the focus would be on the U.S. West Coast, with the main Pacific Fleet homeport of Naval Base San Diego being the obvious first location for fielding.

So against what threat would Aegis at Home be aimed? The challenge that most visibly manifests is North Korea. The country will likely be able to finalize a working ICBM and accompanying warhead by 2020 at the latest and put both into mass production. There is no practical reason that Pyongyang could not field over one hundred such missiles within a decade – something even an expanded and improved GMD system would be unable to cope with alone.

On a day-to-day basis, deterrence will likely work with North Korea. The most likely scenario of a strike against the U.S. would be in the event of the Pyongyang government’s imminent collapse. Such action would be triggered by the regime’s desire to drag as much of the world down with it as possible. Given the nature of the North Korean system and the past fate of similar administrations even without foreign intervention, this risk alone is adequate to justify further investment in missile defense.

However, it may be that concerns over North Korea risk blinding planners to other issues further down the line. As noted, the U.S. military has been vocal in warning of the dangers of Russian cruise missiles, but China’s neighbours are already experiencing a glimpse of a future threat to the U.S. At present, Beijing possesses a powerful but localised land-attack cruise missile capability based upon ground and air-launched weapons such as the DH-10/CJ-10 and its derivatives. In time, these will be supplemented by a new generation of stealth and, eventually, hypersonic missiles. Given that North Korea has broadly limited its cruise missile development to anti-ship variants, it can be seen that the threat from China is the key motivator behind plans by Tokyo to include the SM-6 in its planned Aegis Ashore architecture.

For the most part, it is the launch platforms available to the People’s Liberation Army (PLA) that constrain longer-range cruise missile delivery. The PLA’s main ‘strategic’ cruise missile platform is the H-6K bomber, a 21st-century reincarnation of a 1950s aircraft that has a combat radius of only 1,900 miles. At sea, the Chinese surface fleet’s first priority is currently survival against the U.S. and its allies. As such, the focus is on anti-ship, anti-aircraft and anti-submarine weapons. The PLA’s best option for delivering cruise missiles would be to focus on nuclear submarines. However, the vast majority of the force’s vessels are conventionally powered, limiting their range. Less than ten attack submarines are available, only the later Type 093 models are actually combat worthy, and their current cruise missile capability is unclear.

Nevertheless, Beijing wishes to considerably expand its fleet of nuclear submarines. The clearest indication of this intent has been the construction of what is reportedly the world’s largest submarine production facility in China’s Liaoning Province. Manufacturing of the new Type 095 submarine is expected to begin shortly, a move which, in the words of a recent briefing on the PLA’s capabilities from the Pentagon, would not only “improve the PLAN’s anti-surface warfare capability but might also provide it with a more clandestine land-attack option.” Indications are that up to fourteen Type 95s are planned.

The option also exists for Beijing to bypass traditional platforms and deliver strikes against the U.S. mainland through asymmetric means. Both Russia and Israel have recently practiced the firing of cruise and ballistic missiles from civilian cargo ships. Clandestinely offensively armed civilian vessels have a long history, and China has in recent years shown an increasing tendency to integrate merchant ships into military operations. Hiding missile-armed vessels – possibly remotely controlled given their inevitable post-attack capture or destruction – in the congested shipping lanes of the Eastern Pacific in a time of tension would be far from impossible.

However, would China be willing to launch strikes against military facilities, such as those in San Diego, on the U.S. mainland? Examining the available literature, it is clear that Beijing places great emphasis on attacking U.S. Navy bases in Japan with conventionally armed missiles in the event of a conflict – the notion being that the U.S. is heavily dependent on forward operating bases to sustain combat operations. This theorizing seems likely to have been matched by practical exercises, with satellite pictures revealing what looks very much like practice strikes against mocked-up military facilities in the Gobi desert.

Attacking the U.S. mainland, even if confining activities to military facilities, would, of course, represent a major escalation on limiting an operation to a regional theater. But would the U.S. retaliation be more severe than it might otherwise be? Even if strikes were limited to U.S. bases in Japan, Guam and possibly South Korea, the end result would still be casualties that exceeded those at Pearl Harbour or on 9/11 – and a U.S. government and population seeking vengeance. From Beijing’s standpoint, it would, therefore, be folly not to seek to disable homeland targets of relevance once the capability is there.

When the National Missile Defense Act of 1999 called for the fielding of a National Missile Defense System, both deliverable nuclear weapons and ICBMs were still clearly years away for North Korea. At the time, many advocates of the initiative were accused of trying to mitigate a non-existent challenge. However, whatever the limits of current U.S. defenses against such capabilities, it is undeniable that the country would be in an even worse position now had the effort to pre-empt the threat not been made. There is now again a need to cast a similar eye toward the horizon.

Rowan Allport is a senior fellow and the head of the security and defence division at the Human Security Centre, a London-based think tank. He holds an MA in Conflict, Governance and Development and a Ph.D. in Politics from the University of York.