Defense Secretary Ash Carter provided surprising new details about work -- until now largely classified -- of a secretive office he established three years ago to fast-track development of promising, cutting-edge concepts and technologies to give U.S. forces new advantages against countries such as China and Russia. During an address to the Economic Council of Washington billed as a preview of the fiscal year 2017 budget, Carter touted the work of the Strategic Capabilities Office, a low-profile shop in the...