Defense Secretary Robert Gates is defending his plans to trim more than a billion dollars from the planned system to build a broad missile shield for the US and its allies.
Gates says he's been a supporter of the concept since the days of President Ronald Reagan's Strategic Defense Initiative, dubbed "Star Wars" by its opponents.
But Gates says some of the current program was wasteful or unrealistic.
He told supporters of the system in Congress on Thursday that the US does not need 14 more missile interceptors to defend against a technologically unsophisticated North Korea.
He says he is starting over with another troubled part of the system and making other changes. He did not address plans to base part of the system in Europe.