As a junior senator with presidential aspirations, Barack Obama built his persona in large part around opposition to Bush administration counterterrorism policies, and sponsored a bill in 2005 that would have sharply limited the government's ability to spy on U.S. citizens.
That younger Obama bears little resemblance to the commander-in-chief who stood on a stage in San Jose on Friday, justifying broad programs targeting phone records and Internet activities as vital tools to prevent terrorist attacks and to protect innocent Americans.
Obama, a former constitutional law professor who rose to prominence in part by attacking what he called the government's post-Sept. 11 encroachment on civil liberties, has undergone a philosophical evolution, arriving at what he now considers the right balance between national security prerogatives and personal privacy.