A key Senate panel approved legislation Thursday that would require police to obtain a search warrant from a judge before they can read a private citizen's emails, Facebook messages or other electronic communications. The revised Electronic Communications Privacy Act (ECPA) passed by the Senate Judiciary Committee will now move on to the full Senate for a vote. Passage would be a victory for privacy advocates, who say current privacy rules have been left in the dust by technological progress. Committee Chairman Sen. Patrick Leahy (D-Vt.), who played a key role in drafting the original bill, has called the existing law,...