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.”

Such defense systems are extremely costly” with “their effectiveness often being questionable,” one expert said.

When it comes to protecting U.S. territory from missiles fired by such nuclear-powered countries as Russia, China, and North Korea (which is Trump’s goal in ordering this project), something like Iron Dome would have no capability whatsoever; and