Threats and other harassing communications against federal court personnel have more than doubled in the past six years, from 592 to 1,278, according to the U.S. Marshals Service. This has prompted hundreds of judges to get 24-hour protection from armed U.S. marshals. Many are altering their routes to work, shielding their addresses by paying bills at the courthouse or refraining from registering to vote. Some even pack weapons on the bench. "I live with a constant heightened sense of awareness," said John R. Adams, a federal judge in Ohio who began taking firearms classes after a federal judge's family was slain in Chicago and takes a pistol to the courthouse on weekends. Officials blame the violence on disgruntled defendants whose anger is fueled by the Internet, as well as terrorism and gang cases that bring more violent offenders into federal court. Frustration at the economic crisis might also be a factor.