“THE New Digital Age” is a startlingly clear and provocative blueprint for technocratic imperialism, from two of its leading witch doctors, Eric Schmidt and Jared Cohen, who construct a new idiom for United States global power in the 21st century. This idiom reflects the ever closer union between the State Department and Silicon Valley, as personified by Mr. Schmidt, the executive chairman of Google, and Mr. Cohen, a former adviser to Condoleezza Rice and Hillary Clinton who is now director of Google Ideas.