Rather than trying to protect the US from more than 1,000 nuclear weapons Russia keeps trained on the country, the US's ballistic missile defenses have been nominally to protect against small states with limited arsenals, like North Korea and Iran.
But that changed on Thursday.
Trumps vision of nuclear warfighting takes on Russia
"Our goal is simple: To ensure we can detect and destroy any missile launched against the US any time, any place," Trump said at an event announcing the Missile Defense Review's release.
Missile defense represents one of the most difficult engineering challenges in defense. It requires tracking a warhead traveling at a dozen times the speed of sound through outer space, sometimes paired with decoys, sometimes dipping and diving at random, and firing a second missile to ram into the warhead.
Essentially, missile defense requires hitting a bullet with a bullet, but the bullets are going many times faster and in space.
To combat this challenge, Trump's review proposes looking into things like drones with lasers and F-35 fighter jets to shoot down missiles before they leave earth's atmosphere, space-based interceptors and tracking, and potentially more missile launchers on the ground.
"Given the current ineffectiveness of US BMD, it makes sense to intensify the study of ways to improve it instead of pouring good money after bad into expanding the existing systems," Bruce Blair, a former US Air Force nuclear missile launch control officer and a research scholar at Princeton, told Business Insider.
But even researching ways to stop Russia's missiles from hitting the US could spur Moscow to diversify it's already wildly dangerous nuclear forces , and according to Blair, that brings the world closer to nuclear war.
Russia already states US missile defenses as causes for its new nuclear weapons. In March 2018, Russian President Vladimir Putin hyped up no less than four distinct nuclear systems purpose-built to defeat US missile defenses.
One of these systems, called the Poseidon, ditched the entire concept of an above-ground missile for an underwater torpedo with 100-200 megatons of nuclear explosive power that could cripple entire continents for decades. Russia routinely talks about this doomsday device as a response to US missile defenses.
Additionally, now the US will have to look at every unidentified high-speed undersea movement as a potential world-ending nuclear attack.
"Some of these new weapons deployed in response to BMD have increased the risks of nuclear attack false alarms," said Blair. "During the Cold War none of the false alarms in the US missile attack warning system rose to the level of real-time presidential notification. By contrast in the past 10 years our warning system has notified presidents on multiple occasions and actually trigger the early stages of the presidential launch protocol."
Missile defense a losing battle
Opponents of missile defense say that a good offense is the best defense. How has the US kept Russia's thousands of nukes at bay for decades? Because if Russia ever nuked the US, the US would nuke Russia back with missiles squirreled away in airbases and on submarines.
In this scenario, both countries, and the world, lose.
Trump's review suggests using a drone with a laser on it to pick off missiles before they reach space. But an adversary could simply give the missile a mirrored surface or make it rotate in flight to thwart the laser.
According to Blair, such is the simple truth of missile defense. "It is more expensive to build than for advanced adversarial nations to defeat, and their deployment provokes countermeasures that upset the strategic balance and increase the risks of inadvertent or accidental use of nuclear weapons."