The Missile Defense Agency is exploring whether the Navy's newest interceptor -- originally designed to intercept medium- and intermediate-range threats -- can extend its reach to strike intercontinental ballistic missiles, a new gambit to bolster defense of the United States from North Korean ballistic missile threats, according to a senior defense official. MDA is looking at whether the Standard Missile-3 Block IIA, the newest addition to the Aegis Ballistic Missile Defense system, might "underlay" the Ground-based Midcourse Defense system and...