How Trump’s ‘Iron Dome for America’ upends four decades of nuclear doctrine

Rockets launched towards Israel from the northern Gaza Strip and response from the Israeli missile defense system known as the Iron Dome leave streaks through the sky on May 14, 2021 in Gaza City, Gaza. (Photo by Fatima Shbair/Getty Images)

WASHINGTON — For 40 years America’s missile defense framework has been based on two parallel concepts: First, that kinetic missile defense systems would be designed to physically stop missiles fired by a rogue nation like North Korea or Iran. And second, that those same systems would not be scaled to the level that the US could credibly defend the homeland against a barrage from Russia and China.

It may seem counterintuitive, but the policy case is simple, if somewhat apocalyptic: only the threat of a world-ending nuclear response would keep those powers from launching, and if Moscow and Beijing felt the US could credibly hold them at threat while defending itself, it would cause those competitors to invest even more in nuclear weapons.

And with the stroke of a pen, President Donald Trump upended that balance, with the call for a vastly expanded missile defense system he’s dubbed “Iron Dome for America.”

Trump’s Jan. 27 executive order maintains that the US should “deter” or “defend” against “any foreign aerial attack,” but goes a step further in calling on the Secretary of Defense to submit plans for “Defense […] against ballistic, hypersonic, advanced cruise missiles, and other next-generation aerial attacks from peer, near-peer, and rogue adversaries[.]” 

The shift in US policy would be, in the words of a former US official involved in nuclear operations, a “big change,” one that a bevy of experts interviewed by Breaking Defense say raises questions about the stability of nuclear arms control, the basic feasibility of such a plan and, particularly, how it will change the balance of power in space.

Trump’s vision is “even more bold” than former President Ronald Reagan’s 1983 Strategic Defense Initiative (SDI) program, the former official stressed. “SDI was an R&D program. This is: ‘come back to me in under 120 days with a plan for how you’re going to deploy something.’ So, in that sense, it’s very ambitious,” the former official said.

Already, it has led to swift threats from Moscow.

Discussion of a comprehensive missile defense shield for the US, especially one that includes space-based interceptors — long a nightmare scenario for Russian leaders worried about their nuclear deterrent — was enough for Russian Foreign Ministry official Grigory Mashkov to say any such move “puts an end to the prospects of strategic offensive arms reduction and preservation of strategic stability on the previous terms.”

“It is not ruled out that in the current conditions of confrontation with the West, with its policy of inflicting strategic damage on Russia, we may face the need for moving away from restrictions on nuclear and missile arsenals in favor of their quantitative and qualitative increase,” he wrote in a Russian publication, according to a Jan. 30 report by the state media service TASS.

Mashkov’s comments were tantamount to a threat that Moscow, in an effort to counter Trump’s plan, will bust through the caps placed on both US and Russian nuclear arsenals under the 2011 New START treaty. 

Asked to respond to Mashkov’s suggestion that Moscow may increase its nuclear arsenal, a White House official told Breaking Defense that “President Trump is focused on ensuring Americans stay safe. Russia’s threats suggest this focus is well founded.” The State Department referred to a statement by Secretary Marco Rubio detailing the priorities and mission of the administration. Citing “longstanding SOP [standard operating procedure],” a Pentagon spokesperson said “we don’t discuss hypothetical situations” when asked the same. 

But with Trump’s executive order, that situation is much less hypothetical than at any point since the 1980s, seven experts told Breaking Defense. And while split on whether the risks of Trump’s plan outweigh the benefits with regard to US nuclear security — and in particular whether a space-based capability is a good idea, or even feasible — all agreed on one thing: 

An American Iron Dome system would mean the global nuclear calculus will change dramatically. 

Increased Deterrence or Nuclear Instability?

The fundamental policy argument with regard to homeland missile defense vice peer nuclear powers reflects long-standing differences within the US nuclear literati: does it improve the US ability to deter nuclear attack, or instead increase the likelihood of atomic armageddon?

Ankit Panda, Stanton Senior Fellow at the Carnegie Endowment for International Peace, told Breaking Defense that Moscow’s signature on New START was contingent on there being no fundamental change in Washington’s missile defense policy. 

“The most essential principle of nuclear deterrence is the principle of an assured second strike, and Russia and China are going to ensure that as the United States seeks new types of missile defense modes, including space-based interceptors, they will have the means to retaliate and to penetrate,” Panda explained. 

Further, he said, both Russia and China might not simply move to increase their ICBM arsenals, but also find “alternative” ways of delivering nuclear weapons, such as Russia’s Poseidon underwater autonomous torpedo.

“This [Iron Dome] doesn’t solve the problem of vulnerability,” he argued. “It simply gives America’s adversaries incentives to adapt their own forces to ensure that they’re able to assure their ability to retaliate.”

Already, some of the longstanding arms control threads have frayed between the US and Russia. (China, while a signatory along with the other major nuclear powers of the Nuclear Non-Proliferation Treaty that pledges them to reducing their arsenals over an unspecified time, has never signed up to bilateral arms control with the United States.) 

While Russia in February 2023 suspended its compliance with the treaty citing US and NATO support for Ukraine, President Vladimir Putin at the time still pledged to uphold New START’s weapons caps, refraining from a formal withdrawal. The treaty sets the following limits, according to the State Department website:

• 700 deployed intercontinental ballistic missiles (ICBMs), deployed submarine-launched ballistic missiles (SLBMs), and deployed heavy bombers equipped for nuclear armaments;
• 1,550 nuclear warheads on deployed ICBMs, deployed SLBMs, and deployed heavy bombers equipped for nuclear armaments (each such heavy bomber is counted as one warhead toward this limit);
• 800 deployed and non-deployed ICBM launchers, SLBM launchers, and heavy bombers equipped for nuclear armaments.

Russia moving away from New Start, and its investments in alternative types of nuclear delivery mechanisms, means America is adhering to the old paradigm while ignoring reality, said Rebeccah Heinrichs, a senior fellow at the Hudson Institute and member of the bipartisan Strategic Posture Commission.

“The solution cannot be only offensive investments on the part of the US,” she said. “It has to be defensive investments as well.”

Todd Harrison, a senior fellow at the American Enterprise Institute (AEI), argued: “I think [the Trump order] is largely irrelevant in terms of arms control implications. Arms control is effectively dead already with China building out its arsenal at a rapid pace under no treaty constraints.”

However, Tom Karako, head of the Missile Defense Project at the Center for Strategic and International Studies, argued that some narratives are missing the larger strategic context. Efforts to preserve nuclear stability are “old think” based on a paradigm that has disappeared, he said. 

On the other hand, he cautioned against those who are championing a “faith-based” idea of an invulnerable shield against all missile threats against the US homeland, saying “missile defense is hard. … They’re not taking the threat seriously enough, is what I would say.”

And nothing fits the description of a hard missile defense technology than the most controversial part of Trump’s executive order: space-based interceptors. 

A view of the U.S. Starfish Prime high-altitude nuclear test taken at Maui Station in Hawaii on July 9. 1962. (Credit: Los Alamos National Laboratory)

The SBI Argument: Back To The Future

Experts said it was no surprise that what caught Mashkov’s attention was the executive order’s call for space-based interceptors (SBIs), a technology that has long been a point of contention in the arms control community. 

The concept of space-based interceptors for hitting missiles in their boost phase seconds after launch was a central focus of Reagan’s SDI effort — hence its infamous “Star Wars” nickname — and has been controversial ever since. Scientists then and now are at odds about not only the effects on nuclear stability, but also whether SBIs are affordable, technologically possible, and operationally sound. Further, in more recent years, the debate has broadened to include what impact SBIs might have on the risks of war in space.

“The pursuit of space-based interceptors is a blueprint for instability. History shows that chasing invulnerability only fuels arms races,” Jessica West of Canada’s Project Ploughshares said. “The hard truth? SBI won’t shield us; it will spark a wave of new threats while offering limited real protection in return.” 

With regard to space war, the key issue is that Russia and China not only worry that SBIs will negate their nuclear deterrent, but that they also could be used to kill their satellites, opponents assert.

Victoria Samson, a long-time missile defense analyst at the Secure World Foundation, said that the new order’s resurrection of SBIs will throw a monkey wrench into ongoing talks at the United Nations aimed at creating norms of responsible behavior in space — talks that the State Department and Pentagon helped lead under the Biden administration. 

“These discussions are crucial for the future of space stability,” she told Breaking Defense.

Other analysts point out that America’s adversaries are already deploying weapons on orbit. China, for example, has demonstrated a fractional orbital bombardment system, and American officials have accused Russia of plans to equip a satellite with a nuclear weapon. 

“Our adversaries have not restrained themselves the way we would have liked over the last 40 years,” Heinrichs said. 

While emphasizing the US should not violate the principles of the Outer Space Treaty, which bans weapons of mass destruction in space, Heinrichs said that US space assets have to be protected, and not only by defensive measures.

“We have to … make sure that they know that the United States also has a kill capability in space,” Heinrichs stressed.

But does it work? After all, Star Wars is famous not just for its nickname, but as a wildly expensive program that ultimately was a failure. 

Harrison, in a commentary on AEI’s website, said that while the technology wasn’t ready and the costs were way too high during the Reagan era, that is not the case today. Working SBIs can be deployed, and for a price that is not undoable, he maintained. 

What hasn’t changed, however, is that the laws of physics make the concept of operations for SBIs somewhat dubious, because of the large number of interceptors required even to defeat a small number of incoming enemy missiles, Harrison cautioned.

“The total cost to develop, build, and launch an initial constellation of 1,900 space-based interceptors would likely be on the order of $11 to $27 billion” — with the “catch” that such a constellation could only take on “a maximum of two missiles launched in a salvo,” he wrote. That means that if three missiles were launched simultaneously, at least one would get through, a problem that is known as “absenteeism.” If China and Russia were to launch missiles at the US, one can safely assume it would be more than three. 

“Do we really want to be investing in yet another type of weapon system that does not scale well with the threats we face?” Harrison told Breaking Defense.

The Glide Phase Interceptor is the first system specifically designed to defeat hypersonic threats. (Raytheon graphic)

Doing All The Things: Is It Feasible?

While there is an argument to be made that a “thin” layer of SBIs could be deployed specifically to cover Pacific latitudes to address the Chinese regional threat, Karako stressed that SBIs are not the end-all, be-all for missile defense. Missile defense and space warfare concepts have to be integrated into a larger defense strategy that includes protecting against modern technologies like hypersonic delivery systems and cruise missiles, he said.  

“It’s about raising the threshold for the other guys to be able to cause damage and to inflict all manner of bad effects short of the perceived nuclear threshold,” he said. Doing so means using not just missile defenses but also weapons for “missile defeat” — that is, taking out launch systems before any missiles actually take off.

“There’s no one panacea. There’s no one silver bullet. You have to do all the things,” Karako said.

And therein lies the biggest question of all: what things can actually be achieved within the next four years — especially given that Trump’s plan goes way beyond SBIs to include “an underlayer and terminal-phase intercept” systems, space-based sensors, long-range radars, and “non-kinetic capabilities to augment the kinetic defeat of ballistic, hypersonic, advanced cruise missiles, and other next-generation aerial attacks.”

The former government official said that, given weapon development timelines, the only weapon systems that will be able to actually “shoot down anything” during Trump’s current term are the ship-launched SM-3 Block 2A, being co-developed by the US and Japan, and US Army’s THAAD (Terminal High Altitude Area Defense), which would form the Trump plan’s missile defense “underlayer.” 

“In the last year of the Trump administration, they had proposed a five-year spending plan for SM-3 and THAAD to integrate them into the GMD program. So this is something that the last Trump administration had in the works when they left,” the official said. 

Thus, the former official said, the wisest thing for the Defense Department is to put forward a research, development and testing plan to determine what pieces of the Trump executive order can be deployed by when. 

A key issue, of course, will be funding. And while the Pentagon and the US Space Force are expecting an increased budget, there still will need to be tradeoffs among many competing priorities. The question then becomes what priority the Iron Dome effort will be accorded in those budgetary food fights.

“Right now, we spend about one third of one percent of the defense budget on homeland missile defense, and I’m referring just to the GMD system,” for a total of about “$3 billion” a year, the former official said. “If you believe that this is an important mission, why don’t we raise this to say, one percent, of the DoD budget for homeland defense,” which would raise it to around $8 billion in total. 

At this level of spending, the Trump administration “could do just about everything” in the Iron Dome plan, the former official said, but stressed that it is “a lot of money. … I think they’re in for a rude awakening, if you will, with the numbers.”