As part of a potentially wide-ranging military buildup, President Donald Trump's White House has announced a vague plan to boost America's defenses against ballistic missile attack.
"We will provide our military leaders with the means to plan for our future defense needs," the Trump administration claimed in a statement it published on the White House website just hours after Trump's inauguration on January 20.
"We will also develop a state-of-the-art missile defense system to protect against missile-based attacks from states like Iran and North Korea," the statement continued.
Thing is, the US military already possesses the world's most extensive missile defenses—developed at the cost of hundreds of billions of dollars over a period of decades. And they're already tailored for defeating the kinds of missiles Iran and North Korea are theoretically capable of developing.
And yet, they don't work very well.
It's not clear what Trump could do differently to improve upon existing defenses without squandering potentially billions of dollars on risky new developments. Missile defense, which involves hitting an object traveling many times the speed of sound with another object traveling many times the speed of sound, is hard. And Trump should be careful not to overpromise.
Missile defense became a hot political issue in 1983, when then-President Ronald Reagan launched the Strategic Defense Initiative—"Star Wars," as it was popularly known. Wrongly perceiving that the Soviet Union was pulling ahead of the United States in nuclear missile technology, Reagan pledged to develop non-nuclear missile defenses.
"It took one kind of military force to deter an attack when, we had far more nuclear weapons than any other power; it takes another kind now that the Soviets, for example, have enough accurate and powerful nuclear weapons to destroy virtually all of our missiles on the ground," Reagan explained.
Over the next decade, the Pentagon—at a cost of billions of dollars—experimented with a range missile-killing technologies, including jet-launched missiles and armed satellites. None of the major systems entered frontline service, however.
In the 1990s, US missile-defense strategy shifted. The Soviet Union had collapsed and President Bill Clinton's administration touted new threats from Iran and North Korea, which were both tinkering with modest long-range rockets and rudimentary atomic weaponry.
North Korea subsequently tested its first nuke in 2006 and began slowly working on farther-reaching missiles. Pyongyang has not yet tested a rocket that can hit the United States from the Korean Peninsula.
Meanwhile, President Barack Obama's 2015 nuclear deal with Iran helped to slow if not terminate Tehran's own nuke program. Trump has threatened to cancel the deal, potentially allowing Iran to eventually develop an atomic warhead.
With an eye toward Pyongyang and Tehran, in the 1990s the US military began working on aerial lasers, and missile interceptors launched from ship and ground. These were optimized to destroy small numbers of incoming rockets instead of the potentially thousands of rockets that the Soviets could deploy.
In 2002, President George W. Bush founded the Missile Defense Agency to oversee missile-defense efforts. Spending between $7 billion and $10 billion every year, the agency has concentrated its efforts on a host of space- and ground-based sensors, plus three main weapons—two ground-based systems for shooting down potential Iranian and North Korean nuclear missiles, respectively, plus a sea-based interceptor that's flexible enough to work against either country's rockets.
Well, in theory.
The so-called Ground-Based Interceptor system is a roughly 50-foot-tall missile that launches from an underground silo and aims to hit incoming ballistic missiles during the "mid-course" phase of their flight—basically, the top of their ballistic arc in low orbit.
The US Army operates several dozen of the interceptors at Fort Greely in Alaska plus a few at Vandenberg Air Force Base in northern California, in order to to intercept possible North Korean ballistic missiles heading toward the US West Coast.
To be clear, Pyongyang has not yet developed a rocket that can travel that far. All the same, the MDA is authorized to build up the GBI arsenal to 44 missiles by the end of 2017.
But the $40-billion GBI is unproven—and that's putting it kindly. Missile defense expert Phil Coyle described the missile's performance as "dismal." In 17 test firings since 1999, the GBI has missed its targets nine times.
The sea-based Aegis system is a little more reliable. Being fitted to scores US Navy destroyers and cruisers—43 by 2019, according to the current plan—the Aegis radar and its associated SM-3 missile are less powerful than the GBI missile but somewhat more accurate under test conditions.
The idea is for the warships to patrol along the coast of North Korea or Iran and shoot down ballistic missiles soon after they launch, when they're still at relatively low altitude and slow velocity.
Between 1997 and 2016, the Navy test-fired 40 of the 22-foot-tall SM-3 missile-interceptors and scored 33 hits. But the tests weren't always very realistic. It's not clear that a ship could detect and shoot at a launching rocket —especially a large, powerful intercontinental rocket —fast enough to hit it before it climbs beyond reach. "The boost phase for such missiles terminates at low altitude, making them very difficult to reach," the US National Research Council explained in a 2012 report.
The latest ground-based interceptor uses the same sensor and missile as the sea-based Aegis-SM-3 pairing. The Pentagon built one of these roughly billion-dollar "Aegis Ashore" systems in Romania in 2015 and is working on a second installation in Poland that it hopes to complete in 2018.
Both are meant to defend against "current and emerging ballistic threats from the Middle East," according to the Navy. In other words, Iran.
Since they can't move, the Aegis Ashore missiles can only intercept incoming medium-weight rockets that are aimed relatively near the Aegis installations. That is to say, Europe. Aegis Ashore can't really defend the United States because it's not capable of hitting the big, fast-moving Intercontinental Ballistic Missiles that possess truly global range and could theoretically strike North America after launching from Iran or North Korea.
If Trump wants to take advantage of the decades of work and hundreds of billions of dollars the United States has already poured into missile-defense research and expand missile-defenses quickly—that is, during his first term—he'll have to boost production of an existing system.
And it just so happens that the only existing system with any chance of hitting an incoming Iranian or North Korean ballistic missile from US soil is also America's least reliable missile-interceptor.
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