An executive order said the United States faced a “catastrophic threat” from advanced aerial weapons. But a defense system like Israel’s may not be feasible in the country, which is more than 400 times larger.

President Trump signed an executive order to build an "Iron Dome for America," modeled on Israel’s missile defense system.

President Donald Trump has ordered the development of an "Iron Dome" defense system to shield the United States from an intercontinental missile attack.