TDI Friday Read: Links You May Have Missed, 23 March 2018

To follow on Chris’s recent post about U.S. Army modernization:

On the subject of future combat:

  • The U.S. National Academies of Sciences, Engineering, and Medicine has issued a new report emphasizing the need for developing countermeasures against multiple small unmanned aerial aircraft systems (sUASs) — organized in coordinated groups, swarms, and collaborative groups — which could be used much sooner than the U.S. Army anticipates.  [There is a summary here.]
  • National Defense University’s Frank Hoffman has a very good piece in the current edition of Parameters, “Will War’s Nature Change in the Seventh Military Revolution?,” that explores the potential implications of the combinations of robotics, artificial intelligence, and deep learning systems on the character and nature of war.
  • Major Hassan Kamara has an article in the current edition of Military Review contemplating changes in light infantry, “Rethinking the U.S. Army Infantry Rifle Squad

On the topic of how the Army is addressing its current and future challenges with irregular warfare and wide area security:

Did The Patriot BMD Miss Again In Saudi Arabia?

Apparent trajectory of Houthi Burqan ballistic missile fired at Saudi Arabia on 4 November 2017 [New York Times]

On 4 November 2017, Houthi rebels fired a Burqan 2H (a variant of the SCUD) ballistic missile from Yemeni territory aimed at Riyadh International Airport in Saudi Arabia. The Saudis claimed to have intercepted the missile before it hit using a U.S.-made Patriot PAC-2 ballistic missile defense (BMD) system.

A team of independent analysts have challenged that claim, however. Led by Jeffery Lewis, Director of the East Asia Nonproliferation Program at the Middleberry Institute of International Studies at Monterey, the team analyzed video of an impact near the Riyadh Airport and scattered missile debris. Based on this evidence, they concluded that five Saudi Patriot BMD missiles failed to intercept the incoming missile and that its warhead detonated on the ground just a kilometer away from a busy airport terminal.

The apparent failure of the Patriot BMD continues a string of operational disappointments that extends back to the 1991 Gulf War. Intended for terminal BMD against short and medium range ballistic missile threats, the Patriot forms part of the layered U.S. BMD system, and has also been sold to 14 other countries, including South Korea and Japan.

The credibility of U.S. and regional military defenses against North Korea rests significantly on perceptions of the effectiveness of U.S-made BMD. As President Donald Trump boasted the day after the alleged Saudi missile intercept, “Our [Patriot] system knocked the missile out of the air… That’s how good we are. Nobody makes what we make, and now we’re selling it all over the world.”

How Do You Solve A Problem Like North Korea?

Flight trajectories of North Korean missile tests, May-November 2017. [The Washington Post]

The Democratic People’s Republic of Korea (DPRK) conducted another ballistic missile test yesterday. Following a nearly vertical “lofted trajectory,” the test missile reached a height of 2,800 miles and impacted 620 miles downrange in the Sea of Japan. This performance would give the missile, which the North Koreans have designated the Hwasong-15, a strike range of 8,100 miles, which would include all of the United States.

Appended here is a roundup of TDI posts that address the political and military challenges posed by North Korea. It should be noted that the DPRK nuclear program has been underway for decades and has defied easy resolution thus far. There are no clear options at this stage and each potential solution carries a mix of risk and reward. The DPRK is highly militarized and the danger of catastrophic conflict looms large, with the potential to inflict military and civilian casualties running into the hundreds of thousands or more.

The first set of posts address a potential war on the Korean peninsula.

Chronology of North Korean Missile Development

Insurgency In The DPRK?

U.S. And China: Deterrence And Resolve Over North Korea

Casualty Estimates for a War with North Korea

The CRS Casualty Estimates

The second set of posts look at the DPRK ballistic missile threat and possible counters.

So, What Would Happen If The Norks Did Fire An ICBM At The U.S.?

Aegis, THAAD, Patriots and GBI

Defending Guam From North Korean Ballistic Missiles

The Pros And Cons Of Shooting Down North Korean Ballistic Missile Tests



The Pros And Cons Of Shooting Down North Korean Ballistic Missile Tests

Two THAAD interceptors and a Standard-Missile 3 Block IA missile were launched resulting in the intercept of two near-simultaneous medium-range ballistic missile targets during designated Flight Test Operational-01 (FTO-01) on September 10, 2013 in the vicinity of the U.S. Army Kwajalein Atoll/ Reagan Test Site and surrounding areas in the western Pacific. The test demonstrated the ability of the Aegis BMD and THAAD weapon systems to function in a layered defense architecture. Photos taken by Missile Defense Agency. (Photo Credit: Missile Defense Agency)

On 3 September, North Korea tested what it claimed to be a thermonuclear warhead which can be mounted on a ballistic missile. While analysts debate whether the device detonated actually was a deliverable thermonuclear bomb, it is clear that the regime of Kim Jong Un is making progress in developing the capability to strike the United States and its regional allies with nuclear weapons.

Is there anything that can be done to halt North Korea weapons development and mitigate its threatening behavior? At the moment, there appear to be few policy options, and each of them carries significant risk.

  1. Launch a preemptive military strike.
  2. Enlist or coerce China into reigning in North Korea’s adventurism.
  3. Accept the fact that North Korea is now the ninth nuclear power in the world—with the capability to strike the U.S. and its regional allies with nuclear-armed ballistic missiles—and adopt the Cold War approach of containing it militarily and limiting its nuclear arsenal through negotiation.

Would attempting to shoot down forthcoming North Korean ballistic missile test launches be a viable policy alternative for the U.S. and its allies? Geof Clark proposed this option in a recent post:

I would argue that the U.S. use the United Nations as a forum to define the parameters for any possible North Korean missile launch that should be intercepted with allied BMD [ballistic missile defense] assets If, for example, a North Korean missile looks likely to hit close to Tokyo, based upon the trajectory identified by Aegis ships at sea, then BMD should shoot it down. By making our rules of engagement public, this would provide a clear signal to China and Russia that the U.S. and its allies intend to use their BMD capabilities (and potentially learn from any failures) against live enemy missiles, but also temper the risk of escalation into any further missile volleys between any parties.

A number of commentators questioned why the U.S. or Japan elected not to attempt to intercept North Korea’s 29 August ballistic missile test that flew directly over Japanese territory. A variety of technical and political issues were cited as justification for restraint. The U.S. and Japan resorted to the usual mix of condemnation and calls for further economic sanctions.

What are the arguments for and against a policy of intercepting North Korean missile tests?


  1. The main argument in favor of this is that it could change the narrative with North Korea, which goes like this: Kim’s government stages some provocation and the U.S. and its allies respond with outraged rhetoric, diplomatic moves to further isolate Kim’s regime, and the imposition of a new round of economic sanctions  It is hard to see how much more isolated North Korea can be made, however, and  the vast majority of its trade is with a benevolent China across a porous border. This story has played out repeatedly, yet nothing really changes. Shooting down North Korea’s missile tests could change this stale narrative by preventing it from conducting provocations without consequence.
  2. It would send a strong message to North Korea.
  3. It is not out of line with the provocations North Korea has done over the years (for example: sinking a South Korean patrol boat in 2002).
  4. It is a step short of a preemptive strike by the U.S. and its allies.
  5. It could stall North Korean missile development (especially the ballistic cap, which the North Koreans still have not developed).
  6. It could provide the basis for negotiations.
  7. It is a credible threat (unlike threatening trade sanctions against China to coerce it into restraining North Korea).
  8. It would embarrass Kim’s government by demonstrating that its threats are no longer effective.


  1. Which missile tests would be shot down? The U.S. has already declared that any North Korean missile that appears to be targeted at the territory of the U.S. or its allies would be engaged by BMDs and considered an act of war. (The determination that the 29 August test was not aimed at friendly territory was a major factor in the decision not to engage it.) The Trump administration has repeatedly warned the North Koreans of a massive military response to any perceived attack.
    1. Intercepting a North Korean test flying over Japan or into international waters would likely be interpreted by Kim’s regime as a deliberate escalation of the conflict. Such an act would probably extinguish what some have seen as signals from North Korea of a willingness to engage in diplomatic talks, and could precipitate counter-provocations in what is already a highly tense stand-off.
    2. Some have speculated that the North Koreans may attempt to launch a ballistic missile carrying what many believe to be a recently-tested thermonuclear warhead. The consequences of an attempt to intercept such a test would inevitably be dire.
    3. What about targeting North Korean short-range ballistic missiles, or long-range missile tested at short ranges? Intercepting these tests would pose formidable technical challenges for U.S. and allied BMD systems. The risk of failed intercepts would increase and the level of provocation to the North Koreans would be very high.
  2. China might interpret an attempted intercept as a violation of North Korean sovereignty. Although the Chinese have expressed frustration with North Korea’s behavior, it remains a Chinese client state. While certainly provocative, North Korea’s missile tests over Japan are not a clear cut violation of international law. China remains committed to defending North Korea against foreign threats. Intercepting an allegedly “peaceful” ballistic missile test could easily bring China to North Korea’s overt assistance. This would run contrary to the Trump administration’s avowed policy of enlisting the Chinese to restrain Kim’s government and raises the potential for a direct U.S/China confrontation.
  3. It is not at all clear that key U.S. allies South Korea and Japan would support a policy of intercepting North Korean missile tests not aimed at their territory. The U.S. needs permission from these countries to deploy its theater BMD systems within range of North Korean missiles. South Korea is already ambivalent about hosting U.S. BMDs and Japan has indicated that it will maintain its own policy regarding intercepting potential threats. An aggressive U.S. policy could risk damaging or splitting the alliance.
  4. A vow to intercept North Korean missile tests would place enormous pressure on U.S. and allied BMDs to perform effectively, a capability that remains highly uncertain. While theater BMDs have performed better in tests than the U.S. intercontinental Ground-Based Midcourse Defense (GMD) system, it is unlikely they can intercept every potential target. Any weaknesses demonstrated by theater BMD increases the political effectiveness of North Korea’s putative ballistic missile capability. The current ambiguity works in the favor of the U.S. and its allies. Dispelling the uncertainty would be a high price to pay in any circumstance but defense of U.S. or allied territory.
  5. It is not evident that suppressing North Korean missile tests at this point would have a significant impact on its capabilities. North Korea has already demonstrated that its ballistic missiles work well enough to pose a clear threat to the U.S. and its allies. Further testing would only refine existing technology to reduce the probability of technical failures.

Like the other available policy options, this one too carries a mix of potential benefits and risky downsides. The consequences of attempting to implement it cannot be completely foreseen. What does seem clear is that the existing approach does not seem to have worked. Successfully resolving a problem like North Korea is likely to take time, patience, and no small amount of imagination.


Defending Guam From North Korean Ballistic Missiles

The North Korean ballistic missile threat to Guam [Reuters]

Gerry Doyle has an excellent article in The New York Times exploring the issue of defending the island of Guam from a potential North Korean ballistic missile threat. In response to President Donald Trump’s comments earlier this week, North Korea issued an oddly specific threat to conduct a ballistic missile test targeting the area around Guam.

Key takeaways from the article:

  • The U.S. Terminal High Altitude Area Defense (THAAD) ballistic missile (BMD) system based in South Korea would have no chance of intercepting a Hwasong-12 intermediate-range ballistic missile (IRBM) during its initial ascent (boost-phase). THAAD is not designed for boost-phase intercept.
  • Japan fields a sea-based U.S. Aegis BMD equipped with SM-3 missiles, which is designed to intercept short-, medium-, and intermediate-range ballistic missiles at the middle (mid-course) and final (terminal phase) parts of their flight. It is likely that a Hwasong-12 moving toward Guam would be out of SM-3 range as it passed over Japan, however.
  • Guam itself is defended by a layered BMD system including sea-based U.S. Aegis, THAAD, and Patriot PAC-3 batteries, which are all designed to engage incoming ballistic missiles during mid-course and terminal phase. This is where an intercept would most likely occur.

Despite possessing the technical capability for intercepting a provocative North Korean missile test, Doyle points out a tricky policy problem for the U.S.

If Japan or the United States shoots down the missiles, North Korea could see it as an escalation, prompting a military response. If they do nothing, and allow the North Korean missiles to fly unharmed, it’s unclear how Pyongyang would interpret it.

On the other hand, if they try to intercept the missiles but fail, it could undermine the credibility of both countries’ assurances that their antimissile systems can work.

Stay tuned.

So, What Would Happen If The Norks Did Fire An ICBM At The U.S.?

The intercontinental ballistic missile Hwasong-14 is allegedly seen during its test in this undated photo released by North Korea’s Korean Central News Agency (KCNA) in Pyongyang, July, 4 2017. [KCNA/via REUTERS]

This past July, North Korea conducted a pair of test launches of a new intercontinental ballistic missile (ICBM), which it calls the Hwasong-14 (“Mars”). While North Korean leader Kim Jong-Un claimed the vehicle can strike “any region and place any time,” skeptical Western military analysts concede it likely has the range to reach much of the United States. (There is disagreement as to whether the Hawsong-14 can actually deliver a nuclear warhead to targets in the Eastern U.S., but analysts concur that it can strike Hawaii, Alaska, and the Western U.S.)

According to a recent Defense Intelligence Agency assessment, the North Koreans have developed nuclear warheads small enough to be mounted on its ballistic missiles, including the Hwasong-14. The DIA estimate also credited the North Koreans with a stockpile of up to 60 nuclear weapons, though some outside analysts believe it to be fewer.

Earlier this week, North Korean Foreign Minister Ri Yong Ho vowed that, “Should the U.S. pounce upon the DPRK (Democratic People’s Republic of Korea) with military force at last, the DPRK is ready to teach the U.S. a severe lesson with its strategic nuclear force.”

What real capability does a functional ICBM with nuclear warheads provide the North Koreans? What would happen if they did attempt a nuclear attack on the U.S.? The answer is that no one, including the North Koreans, knows with any certainty.

Hitting A Bullet With A Bullet: Ballistic Missile Defense

Shooting down an incoming ICBM has been likened to “hitting a bullet with a bullet”; however IBCMs travel at speeds eight times faster than a bullet. The only current ballistic missile defense (BMD) system the U.S. possesses capable of intercepting ICBMs is the Ground-Based Midcourse Defense (GMD), a combination of Ground Based Interceptors (GBIs), long-range radars, and a distributed fire control system. There are only two existing GMD emplacements, one at Ft. Greely, Alaska, and the other at Vandenberg Air Force Base in California. The Ft. Greely site houses 30 GBIs, though ten more are scheduled for deployment there, and four are based at Vandenberg, for a total of 44 by the end of 2017.

GMD has demonstrated a mixed track record in tests, achieving 10 intercepts in 18 attempts (55%). U.S. Air Force General Lori Robinson, commander of the U.S. Northern Command, nevertheless told the Senate Armed Services Committee in April that “Today we have exactly what we need to defend the United States of America against North Korea.”

This conclusion has been questioned by the Government Accountability Office, National Academy of Sciences, and the Union of Concerned Scientists, who have all sharply criticized GMD’s technical viability and accuracy. GMD’s advocates claim that using a “shoot-look-shoot” tactic, which would target an incoming ICBM with successive GBIs raises the odds of success. However, the Union of Concerned Scientists have calculated that if the North Koreans were to fire a volley of five ICBMs and each GBI had a 50% chance of a successful interception, there would be a 28% chance that one of the North Korean missiles would get through.

The U.S. fields three regional or theater BMDs, Aegis, Patriot, and Terminal High Altitude Area Defense (THAAD). These were developed to engage short- to intermediate-range ballistic missile threats, however, not ICBMs, which travel much faster and higher. They are, however, a key component in defending South Korea, Japan, and other countries in the region from North Korean ballistic missile attack.

Another potential ICBM defense would be to interdict the missiles before they are launched. Liquid-fueled missiles such as the Hwasong-14 require hours to fuel with highly volatile propellants, rendering them vulnerable to conventional air or missile attack. While the U.S. and the South Koreans are able to detect test preparations ahead of time, they have not been able to pinpoint launch sites in real time before firing. The North Koreans have developed mobile launchers and capabilities for quickly firing missiles from remote areas of the country far from existing infrastructure. (As the U.S. and its Coalition allies discovered in the 1991 Gulf War, interdicting mobile ballistic missile launchers is a difficult task even with complete air superiority.) Successfully interdicting a North Korean ICBM launch would require far better U.S./South Korean intelligence/surveillance/reconnaissance capabilities than those currently available.

“If he says they can’t hit Nevada on a clear day, you better believe it”

Should a North Korean ICBM successfully evade U.S. missile defenses, what would happen next? This is also a very good question with no clear answer. Conducting a successful ICBM attack with a nuclear weapon is an extraordinarily challenging technical task, which requires a lot of sophisticated technology to function flawlessly under rigorous conditions. The U.S. has tested an ICBM/nuclear warhead under operational conditions only once, with Shot FRIGATE BIRD during Operation DOMINIC in 1962. The submarine U.S.S. Ethan Allen fired a Polaris A2 ballistic missile armed with a 600-kiloton W-47 thermonuclear warhead, which detonated successfully in the air 2,000 meters from target over Johnston Island, 120 miles away in the Pacific Ocean.

Some analysts believe that the re-entry vehicle (RV) from the 28 July Hwasong-14 test broke up before landing. It is unlikely a real warhead would have survived such a failure. RV’s house a ballistic missile’s warhead, protecting it from the stresses of flight and atmospheric reentry and provide the terminal guidance onto the target. The U.S. required years of extensive, expensive testing before it perfected an ICBM RV. While North Korea has developed effective RVs for its shorter range ballistic missiles, the lack of a durable one for the Hwasong-14 will degrade its potential effectiveness and accuracy for the time being.

If a Hwasong-14 RV did manage to survive reentry, what then? On target is a relative term, even with nuclear weapons. North Korea is believed to have developed only kiloton-range fission-type nuclear devices, not megaton-range thermonuclear warheads. Size imposes limits on the yield of fission devices. The Hwasong-14 is estimated to be capable of delivering a payload of only 500 kg or less at intercontinental ranges, which would have to include the RV and the warhead. To date, the North Koreans have tested devices yielding  10-15 kilotons. With the addition of fission-boosting using deuterium, lithium-6, or tritium, the total yield might be significantly enhanced. Some analysts credit the North Koreans with the capability for building a boosted, composite pit device yielding somewhere in the 30-kiloton range. For comparison’s sake, the Fat Man fission bomb dropped on Nagasaki in 1945 had a yield of approximately 21 kilotons.

There is no firm estimate of the Hwasong-14’s circular error of probability (CEP) or the radius within which 50% of missile impacts would theoretically be expected to land, a standard measure of ballistic missile accuracy. By scaling up the accuracy of the Hwasong-14’s SCUD missile antecedent to intercontinental range, one analysis estimated a CEP of 30 kilometers. A blunt-body shaped RV and hasty launches from remote sites would hamper accuracy as well. It is also plausibly arguable that North Korea might be capable of matching the 3-5 kilometer CEP of the first Soviet ICBM, the R-7.

With a CEP of 30 kilometers, it would be entirely possible for a Hwasong-14 to fly successfully, evade U.S. BMDs, detonate effectively, and still completely miss a target as large as Los Angeles.

Map of a hypothetical strike on Los Angeles with a 30-kiloton nuclear airburst, delivered by a ballistic missile with a 30 kilometer CEP. The red cross represents the designated ground zero, the blue lines indicate the CEP radius, and the red dot represents the radius of 5-psi overpressure effects from the nuclear explosion. [MISSILEMAP by Alex Wellerstein, RESTRICTED DATA: The Nuclear Secrecy Blog ]

A CEP of 3-5 kilometers would greatly increase the probability of even a near-miss hitting a densely populated section of the city, killing and injuring tens or hundreds of thousands, if not more.

Map of a hypothetical strike on Los Angeles with a 30-kiloton nuclear airburst, delivered by a ballistic missile with a 3-5 kilometer CEP. The red cross represents the designated ground zero, the blue lines indicate the CEP radius, and the red dot represents the radius of 5-psi overpressure effects from the nuclear explosion. [MISSILEMAP by Alex Wellerstein, RESTRICTED DATA: The Nuclear Secrecy Blog ]

A Catastrophe Of Unimaginable Consequences

Close observers of the North Korean nuclear and missile programs understand that the July missile tests represent a nominal, but real, capability for delivering a nuclear ballistic missile strike against the U.S. The challenges in improving this capability are formidable, but they are technical in nature and there is no reason to believe the North Koreans cannot solve them in time. A true game changer would be the ability to deliver a thermonuclear warhead yielding hundreds of kilotons or more. Some analysts see this development as inevitable.

Regardless of the scenario, the launch of any North Korean nuclear-armed ICBMs toward the United States could only be regarded as a catastrophic failure of American foreign and military policy. The consequences of even a limited nuclear strike on U.S. soil would be effectively unimaginable, far beyond the death, destruction, and inevitable reality of retaliation-in-kind against the North Korean regime.

It would also represent a failure of any rational North Korean defense policy as well, since the only value ICBMs have to North Korea is in deterring foreign attack. They are militarily useless to prevent a counterattack that would invariably destroy Kim Jong-Un’s government. Their only value lies in the political threat to use them.

It would seem then that the U.S. and North Korea share a common interest in seeing that North Korea’s ICBMs are never used. The only sensible means to that end lie in deterrence and negotiation.