Robust, credible and layered missile defense is the foundation of deterrence

In 2005, an anticipated missile threat to the homeland prompted the expeditious fielding of a missile defense capability to defend the United States. Today, that threat is real, expanding, and most likely nuclear. Our defense needs to also be real and effective for today and into the future.

A recent report by the think tank Rand estimates North Korea has 50 nuclear weapons in its arsenal and, by 2027, will have in excess of 200 and several dozen intercontinental ballistic missiles to complement its several hundred theater ballistic missiles. The director of national intelligence’s 2021 Annual Threat Assessment clearly states: “North Korea will be a [weapons of mass destruction] threat for the foreseeable future, [and] the country is actively engaged in ballistic missile research and development.”

While we must not cast diplomacy aside, we should recognize deterrence is an essential element in any strategy for dealing with the North Korean nuclear missile threat. Deterrence matters, and Adm. Charles Richard, commander of U.S. Strategic Command, framed the point well when he said: “A robust and credible layered missile defense system paired with our conventional and nuclear force capabilities provide the ability to deter strategic attacks, deny benefits, and impose costs against any potential adversary.”

Deterrence discourages an adversary by instilling doubt and anxiety in their decision calculus. Our Ballistic Missile Defense System “denies benefit” by planting that seed of doubt in North Korea’s decision calculus; the doubt that an attack on the United States will succeed.

Today, our defense rests on the Ground-based Midcourse Defense system, or GMD, and its 44 interceptors. But that alone is not going to be adequate to deal with the threats of 2027. Defending our homeland is vital. Looking to the next decade, we need to stay ahead of our threats. Our concerns are four-fold: technology, numbers, layers and sensors.

Technology: Advancing the effectiveness of our missile defense capabilities is extremely important. The Missile Defense Agency recently awarded two contracts, to two teams, to competitively develop a Next Generation Interceptor, or NGI, to overcome the shortcomings in the current interceptor fleet and provide a path to outpace future threats. This competitive development cycle will add up to 20 new interceptors to the inventory. As long as the program enjoys support and an adequate budget from the Department of Defense and Congress, we are on solid ground for the technology.

Numbers: A point of concern, though, is the math: 20 new intercepts plus the current 44 will give us 64. If Rand is anywhere close, we could be outnumbered by the end of the decade. More important, we certainly cannot accept a 1-to-1 exchange ratio when we are dealing with nuclear missiles coming toward the homeland.

Layers: No single defensive system is successful 100 percent of the time, and we cannot base the defense of America solely on the hope of success for every GMD intercept. We need the opportunity for a second engagement in the event GMD’s interceptors do not destroy the in-bound threat. Developing a layered defense is a vital strategy for our nation. We have the technology. MDA recently demonstrated the SM-3 Block 2A missile could intercept an ICBM. All we need now is an aggressive plan to truly build our layered approach for homeland missile defense.

Sensors: Lastly, our future missile defense architecture needs to have the right capabilities to “see the threat” and enable successful defenses. As Gen. John Hyten, vice chairman of the Joint Chiefs of Staff, has stated: “If you can’t see it, you can’t shoot it. And if you can’t see it, you can’t deter it either.” Today’s sensor suite — a handful of terrestrial sensors — needs to advance to the next generation: space-based sensors. Our defenses need to be able to pick out the lethal objects in a cluster of countermeasures. Further, our sensors need to provide “fire control quality” information to the defensive interceptors. While a space-based sensor architecture will be expensive, it will cost far less — in both dollars and operational risk — than relying solely on a terrestrial network.

We cannot take our foot off the pedal. While it will likely take six to seven years to field our NGI, rest assured our adversaries are not standing still. The threat is real: in North Korea today, and potentially Iran tomorrow.

NGI funding and robust competition within the program to limit technical risk and accelerate deployment are essential to stay on plan. The DoD needs to initiate a real commitment to developing the homeland’s layered defense and creating a robust, space-based missile defense sensor architecture. Development of an Aegis- and Terminal High Altitude Area Defense-based homeland defense architecture, which could be rapidly fielded, would provide the homeland an initial layered defense. Development of a space-based, discriminating sensor would enhance GMD’s and an underlayer’s performance, as well as contribute to improved theater missile defense operations.

With the upcoming debates on budget, there are sure to be opponents who will challenge the investment in our missile defenses. The issue is not how much the defense costs; the question is how much risk are you willing to buy as nuclear weapons fly toward America.

Deterrence is clearly the best approach. America needs a robust and credible layered missile defense system to deter and, if necessary, defeat a North Korean missile attack on our homeland.

Retired U.S. Air Force Maj. Gen. Punch Moulton served as the director for operations at U.S. European Command. He currently leads the Missile Defense Agency’s biannual missile defense war game. He is also the vice president for defense support and cyber strategies at Stellar Solutions. Retired U.S. Army Maj. Gen. Francis Mahon served as the director for strategy, policy and plans at North American Aerospace Defense Command and U.S. Northern Command. He also worked as the director for testing at the Missile Defense Agency. He is currently an independent aerospace defense contractor and an advisor for Stellar Solutions.

2005年，由于预期本土将面临导弹威胁，美国迅速部署了导弹防御系统以保卫自身安全。如今，这种威胁真实存在，且不断扩大，极有可能涉及核威胁。因此，我们的防御体系必须切实有效，以应对当前及未来的挑战。

兰德公司最近的一份报告估计，朝鲜目前拥有50枚核武器，到2027年，核武器数量将超过200枚，此外还将拥有数十枚洲际弹道导弹，以补充其数百枚战区弹道导弹。美国国家情报总监在2021年度威胁评估报告中明确指出：“在可预见的未来，朝鲜将构成大规模杀伤性武器威胁，并且该国正在积极进行弹道导弹的研发。”

我们固然不能放弃外交手段，但必须认识到，威慑是应对朝鲜核导弹威胁任何战略中不可或缺的要素。威慑至关重要，美国战略司令部司令查尔斯·理查德海军上将对此做了很好的阐述，他指出：“一个强大而可靠的多层导弹防御系统，结合我们的常规和核力量，能够有效威慑战略攻击，剥夺潜在对手的利益，并使其付出代价。”

威慑通过在对手的决策过程中植入怀疑和焦虑来阻止其行动。我们的弹道导弹防御系统通过在朝鲜的决策过程中植入怀疑的种子——即怀疑对美国的攻击能否成功——来“剥夺其获益”。

如今，我们的防御主要依赖于陆基中段防御系统（GMD）及其44枚拦截导弹。但仅靠这些不足以应对2027年的威胁。保卫国土至关重要。展望未来十年，我们需要领先于威胁。我们面临的挑战主要体现在四个方面：技术、数量、防御体系和传感器。

技术：提升导弹防御能力至关重要。导弹防御局近期向两支团队分别授予两份合同，以竞争性地研发下一代拦截器（NGI），旨在克服现有拦截器部队的不足，并为应对未来威胁铺平道路。这一竞争性研发周期将为导弹防御系统新增至多20枚拦截器。只要该项目能够获得国防部和国会的支持和充足的预算，我们的技术发展就稳如磐石。

数字：然而，一个令人担忧的问题是数量：新增的20个拦截点加上现有的44个，总共将达到64个。如果兰德的预测接近这个数字，到本十年末，我们可能会在数量上处于劣势。更重要的是，面对来袭的核导弹，我们绝不能接受1比1的交换比例。

多层防御：没有任何单一的防御系统能够百分之百成功，我们不能仅仅寄希望于每次陆基中段防御系统（GMD）拦截都能成功。我们需要在GMD拦截器未能摧毁来袭威胁的情况下，进行二次拦截。发展多层防御对我国至关重要。我们拥有相应的技术。导弹防御局（MDA）最近演示了SM-3 Block 2A导弹拦截洲际弹道导弹的能力。我们现在需要的是一个积极主动的计划，真正构建我们国土导弹防御的多层防御体系。

传感器：最后，我们未来的导弹防御体系必须具备“识别威胁”并成功防御的能力。正如参谋长联席会议副主席约翰·海顿将军所言：“如果看不到它，就无法击落它。如果看不到它，也无法威慑它。”如今的传感器系统——仅由少数地面传感器组成——需要升级到下一代：天基传感器。我们的防御系统必须能够在众多反制措施中识别出致命目标。此外，我们的传感器还需要向防御拦截器提供“火控级”信息。虽然天基传感器体系造价昂贵，但与仅仅依赖地面网络相比，无论从资金还是作战风险方面，其成本都将大大降低。

我们不能放松警惕。虽然部署下一代智能系统可能需要六到七年时间，但请放心，我们的对手绝不会坐以待毙。威胁真实存在：今天在朝鲜，明天就可能在伊朗。

NGI项目的资金投入以及项目内部为限制技术风险和加快部署而展开的良性竞争，对于确保项目按计划进行至关重要。国防部需要真正致力于发展国土多层防御体系，并构建强大的天基导弹防御传感器架构。开发基于宙斯盾和末段高空区域防御系统的国土防御架构，并使其能够快速部署，将为国土提供初步的多层防御。开发天基识别型传感器将提升陆基中段防御系统（GMD）及其底层防御系统的性能，并有助于改进战区导弹防御作战。

即将到来的预算辩论中，肯定会有人质疑我们对导弹防御系统的投资。问题的关键不在于防御成本是多少，而在于当核武器飞向美国时，你愿意承担多大的风险。

威慑显然是最佳途径。美国需要一套强大且可靠的多层导弹防御系统，以威慑朝鲜对美国本土的导弹袭击，并在必要时予以挫败。

美国空军退役少将庞奇·莫尔顿曾任美国欧洲司令部作战主任。他目前领导导弹防御局每两年一次的导弹防御演习。他同时也是Stellar Solutions公司的国防支持和网络战略副总裁。美国陆军退役少将弗朗西斯·马洪曾任北美防空司令部和美国北方司令部战略、政策和计划主任。他还曾担任导弹防御局测试主任。他目前是一名独立的航空航天国防承包商，也是Stellar Solutions公司的顾问。