The United States is estimated to have spent more than $400 billion on the kinds of antimissile goals that the president now says will provide “for the common defense.”

The document titled "The Iron Dome for America" outlines the construction of a "next-generation missile defense shield" and is currently a general directive. Signed by Donald Trump, it requires the Secretary of Defense to present a plan for the defense system to the President within 60 days.

The first Trump administration floated a space weapon concept in March 2018: a neutral particle beam in space. But it ultimately shelved the idea because of the massive amount of power needed to destroy a missile with directed energy.