Rule Changes Would Give FBI Agents Extensive New Powers The Justice Department will unveil changes to FBI ground rules today that would put much more power into the hands of line agents pursuing leads on national security, foreign intelligence and even ordinary criminal cases. The overhaul, the most substantial revision to FBI operating instructions in years, also would ease some reporting requirements between agents, their supervisors and federal prosecutors in what authorities call a critical effort to improve information gathering and detect terrorist threats. The changes would give the FBI's more than 12,000 agents the ability at a much earlier stage to conduct physical surveillance, solicit informants and interview friends of people they are investigating without the approval of a bureau supervisor. Such techniques are currently available only after FBI agents have opened an investigation and developed a reasonable suspicion that a crime has been committed or that a threat to national security is developing. It also would rewrite 1976 guidelines established after Nixon-era abuses that restrict the FBI's authority to intervene in times of civil disorder and to infiltrate opposition groups....