The American interceptor has a spotty track record, succeeding in nine of 17 attempts since 1999. The most recent test, in June 2014, was a success, but that followed three straight failures. The system has evolved from the multibillion-dollar effort triggered by President Ronald Reagan’s 1983 push for a “Star Wars” solution to ballistic missile threats during the Cold War — when the Soviet Union was the only major worry.| Report Focus News

North Korea is now the focus of U.S. efforts because its leader, Kim Jong Un, has vowed to field a nuclear-armed missile capable of reaching American territory. He has yet to test an intercontinental ballistic missile, or ICBM, but Pentagon officials believe he is speeding in that direction.